# Fileset

[Chem. Mater. 2026, 38, 5579-5587.pdf](https://mdr.nims.go.jp/filesets/619ec4a1-2fd9-489a-b0da-a45c1bac148e/download)

## Creator

[Marcela Calpa](https://orcid.org/0000-0003-4934-4595), [Randy Jalem](https://orcid.org/0000-0001-9505-771X), Taiga Ozawa, Minako Nishioka, Anna Myojin, [Gen Hasegawa](https://orcid.org/0000-0002-9297-6902), [Naoaki Kuwata](https://orcid.org/0000-0002-0736-6967), [Shoichi Matsuda](https://orcid.org/0000-0002-0640-3404), [Kei Kubota](https://orcid.org/0000-0001-8941-3650), [Kazunori Takada](https://orcid.org/0000-0001-7568-1806)

## Rights

[Creative Commons BY Attribution 4.0 International](https://creativecommons.org/licenses/by/4.0/)

## Other metadata

[Modulating Redox Pathways in Manganese-Based Disordered Rocksalt Cathodes via Molybdenum Incorporation](https://mdr.nims.go.jp/datasets/bad06e6a-a228-4b7a-af7c-0b083c8c7539)

## Fulltext

Modulating Redox Pathways in Manganese-Based Disordered Rocksalt Cathodes via Molybdenum IncorporationModulating Redox Pathways in Manganese-Based DisorderedRocksalt Cathodes via Molybdenum IncorporationMarcela Calpa,* Randy Jalem, Taiga Ozawa, Minako Nishioka, Anna Myojin, Gen Hasegawa,Naoaki Kuwata, Shoichi Matsuda, Kei Kubota, and Kazunori TakadaCite This: Chem. Mater. 2026, 38, 5579−5587 Read OnlineACCESS Metrics & More Article Recommendations *sı Supporting InformationABSTRACT: Cation-disordered rocksalt oxides offer broadcompositional flexibility and high theoretical capacities, but theirelectrochemical performance is often limited by uncontrolledcompetition between transition metal and oxygen redox processes.In particular, controlling the balance between Mn and O redoxactivities remains a key challenge in Mn-based disordered oxides.Here, a previously unexplored compositional space in theLi−Mn−Mo−O system is investigated, revealing that Moincorporation systematically alters the electronic structure andredox behavior of Mn-based disordered rocksalt oxides. Mo dopinglowers the average Mn oxidation state, thereby stabilizing a Mn-dominated charge-compensation mechanism. Combined spectroscopic characterization and first-principles calculations reveal a shiftin charge compensation from oxygen-centered to Mn-centered redox processes with Mo doping. As a result, Li1.25Mn0.5Mo0.25O2delivers a reversible capacity exceeding 300 mAh g−1 with enhanced electrochemical stability. These findings demonstrate thattargeted compositional and electronic structure modulation enables effective control of redox pathways in cation-disordered oxidesand offers design principles for stable, high-capacity Mn-based cathode materials.■ INTRODUCTIONCation-disordered rocksalt oxides represent a chemicallyversatile class of transition metal oxides that expand thecompositional landscape for designing high-capacity electrodematerials beyond conventional layered structures. Theircompositional flexibility and high lithium contents enabletheoretical capacities exceeding those of traditional layeredoxides.1 However, their electrochemical behavior emerges froman intricate interplay between local structure, electronicconfiguration, and redox chemistry, making the rational designof stable high-capacity compositions a fundamental challengein materials chemistry.2,3Among disordered rocksalt oxides, Mn-based compoundsare particularly attractive because of the natural abundance,low cost, and environmental compatibility of manganese.Nevertheless, Mn-rich disordered oxides frequently exhibitpronounced oxygen redox activity, which is often accompaniedby structural degradation and irreversible oxygen loss, resultingin limited electrochemical stability.4 Recent studies haveshown that the balance between Mn-centered and oxygen-centered redox processes is influenced by local coordinationenvironments, lithium excess levels, and the electronicstructure of transition metal cations.1,2Despite these advance-ments, achieving controlled and stable Mn-dominated redoxbehavior in disordered rocksalt systems remains an unresolvedchallenge, limiting their practical application.5In this work, Li-rich Mn−Mo disordered rocksalt oxidesderived from the solid-solution system 3/2Li4/3Mn2/3O2-xLiMoO2 are investigated as a platform for modulating redoxchemistry through compositional and electronic structuretuning. By combining electrochemical measurements withspectroscopic characterization and first-principles calculations,the relationship between composition, electronic structure, andcharge-compensation mechanisms is elucidated.■ EXPERIMENTAL SECTIONSynthesis and CharacterizationDisordered rocksalt-type lithium metal oxides consisting of solidsolutions of 3/2Li4/3Mn2/3O2-xLiMoO2 are synthesized for x having avalue of 0, 0.1, 0.25, and 0.5. To synthesize 3/2Li4/3Mn2/3O2-xLiMoO2 compounds, Li4/3Mn2/3O2 and LiMoO2 in stoichiometricamounts are ball milled in a planetary Mono mill (Fritsch, Pulveristte6) and subject to a rotation of 350 rpm for a total milling time of 90 h,under Ar atmosphere. The ball-milling process is carried out inalternating cycles of 30 min of milling followed by 30 min of rest.Received: January 31, 2026Revised: May 15, 2026Accepted: May 19, 2026Published: May 29, 2026Articlepubs.acs.org/cm© 2026 The Authors. Published byAmerican Chemical Society5579https://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−5587This article is licensed under CC-BY 4.0Downloaded via NATL INST FOR MATLS SCIENCE (NIMS) on July 9, 2026 at 09:07:43 (UTC).See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Marcela+Calpa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Randy+Jalem"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Taiga+Ozawa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Minako+Nishioka"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Anna+Myojin"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Gen+Hasegawa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Naoaki+Kuwata"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Naoaki+Kuwata"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Shoichi+Matsuda"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Kei+Kubota"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Kazunori+Takada"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/showCitFormats?doi=10.1021/acs.chemmater.6c00304&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?goto=articleMetrics&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?goto=recommendations&?ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?goto=supporting-info&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=tgr1&ref=pdfhttps://pubs.acs.org/toc/cmatex/38/11?ref=pdfhttps://pubs.acs.org/toc/cmatex/38/11?ref=pdfhttps://pubs.acs.org/toc/cmatex/38/11?ref=pdfhttps://pubs.acs.org/toc/cmatex/38/11?ref=pdfpubs.acs.org/cm?ref=pdfhttps://pubs.acs.org?ref=pdfhttps://pubs.acs.org?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://pubs.acs.org/cm?ref=pdfhttps://pubs.acs.org/cm?ref=pdfhttps://creativecommons.org/licenses/by/4.0/Figure S1 shows the evolution of the XRD pattern during the ball-milling process. To synthesize Li4/3Mn2/3O2, Li2CO3 (99.9%,Kojundo Chemical Co., Ltd.) and Mn2O3 (99.9%, Kojundo ChemicalCo., Ltd.) are used as precursors. Li2CO3 with 10 wt % excess andMn2O3 are mixed using a mortar and pestle for 15 min. The reagentmixture is placed on an alumina crucible and heated at 800 °C for 10h. Heating is carried out using a tube furnace under N2 (80 vol %)and O2 (20 vol %) flowing, with a heating rate of 5 °C/min. Tosynthesize LiMoO2, Li2CO3 (99.9%, Kojundo Chemical), MoO3(99.5%, Kanto Chemical Co., inc), and C (Acetylene black, HS100,Denka Co., Ltd.) are used as precursors in a 1:2:1.5 molar ratio.Li2CO3, MoO3, and C are mixed using a mortar and pestle for 15 min.The reagent mixture is placed on an alumina crucible and heated at800 °C for 10 h. Heating is carried out using a tube furnace under Arflowing, with a heating rate of 5 °C/min.X-ray diffraction (XRD) patterns are collected using a RigakuSmartLab diffractometer with Cu−Kα radiation over a 2θ range of10−90° and a step size of 0.01°. Morphology is observed by scanningelectron microscopy (SEM) performed with a JEOL JSM-7800F.Transmission electron microscopy (TEM) images and electronenergy loss spectroscopy (EELS) are performed on a JEOL JEM-ARM200F microscope. 7Li magic-angle spinning (MAS) NMRspectra are recorded on a JEOL 400 spectrometer operating at a7Li resonance frequency of 155.4 MHz. Samples are spun at 20 kHzusing a 3.2 mm MAS probe, and spectra are acquired with aspin−echo pulse sequence at room temperature. The π/2 pulse lengthwas 2.8 μs, the recycle delay was 1.0 s, and 512 scans wereaccumulated. The 7Li chemical shifts are referenced to 1 mol L−1 LiClaqueous solution at 0 ppm.All-solid-state batteries are constructed as follows. 3/2Li4/3Mn2/3O2-xLiMoO2 compound powders, argyrodite-type solidelectrolyte (Mitsui Kinzoku), and acetylene black (HS100, DenkaCo., Ltd.) are mixed in a 5:5:2 weight ratio, respectively, using amortar and pestle for 15 min, to prepare the positive compositeelectrode. To construct all-solid-state batteries, a bilayer pellet (φ =10 mm) consisting of the positive composite electrode (5 mg, 6.4 mg/cm2) and argyrodite-type solid electrolyte (Mitsui Kinzoku, 100 mg)is obtained by pressing under 185 MPa at room temperature. Indium(Nilaco Corp.) and lithium (Honjo Metal Co., Ltd.) foils are attachedto the opposite side of the solid electrolytes by pressing under 260MPa. The resulting solid-state battery is sandwiched between twostainless steel rods, which serve as current collectors for both positiveand negative electrodes, and the assembly is secured with screwstightened to 6 N·m each (Figure S2).Charge−discharge measurements are carried out in an environmentof 50 °C using a constant current (CC) mode at 10 mA g−1, within avoltage window of 1.5 V−4.2 V vs Li. All electrochemical tests areperformed using a charge−discharge test system (BCS-805, Biologic).Gas evolution is monitored using a Canon Anelva QuadrupoleMass Spectrometer (M-401GA-DM) as previously described.6 Forthis analysis, all-solid-state batteries are assembled according to theprocedure outlined above but employing a customized cell equippedwith a gas inlet and outlet. To ensure sufficient detection of gasevolution above background levels, 20 mg of the positive compositeelectrode was used. The charge−discharge tests were carried out atroom temperature.Computational MethodsDensity functional theory (DFT) calculations are carried out usingthe Vienna Ab Initio Simulation Package (VASP). It employs thegeneralized gradient approximation (GGA) approach with theprojector-augmented-wave (PAW) basis set.7 The structure coor-dinate data for the Fm3̅m disordered rocksalt Li1-nMnO, where Mrepresents the transition metal species and n denotes its fractionoccupying the cation sublattice, is taken from an experimental report.8Two compositions are considered: Li1.25Mn0.6875O2 andLi1.25Mn0.5Mo0.25O2. The unit cell is expanded into a 2 × 2 × 2supercell, which is then used as a template for generating 500 randomconfigurations of Li−Mn−Mo-vacancy arrangements. Next, a total of10 structures with the lowest electrostatic Ewald energies aresubjected to DFT geometry optimization. The lowest DFT total-energy structure is then chosen as the representative for furtheranalyses. Structure geometry optimization is performed with spinpolarization switched on. The kinetic energy cutoff is set to 520 eV,and the k-point is fixed to at least 1000 with a γ-point centered mesh.The following pseudopotentials are used: Li with s shell treated asvalence states, standard Mn, Mo with p shell treated as valence states,and standard O. The strong on-site Coulomb interaction is accountedby employing the GGA + U scheme.9 The effective Hubbard Uparameters for Mn-3d and Mo-4d are set to 4.9 and 6.3 eV,respectively.10 The optB88-vdW functional is used to describe the vander Waals interaction in the structures.11 Convergence criteria forenergy and force are fixed to <1 meV/atom and <0.01 eV/Å,respectively.■ RESULTS AND DISCUSSIONFigure 1 shows the XRD patterns of 3/2Li4/3Mn2/3O2-xLiMoO2 compounds with x having a value of 0, 0.1, 0.25,and 0 .5 (L i 1 . 3 3Mn0 . 6 7O2 , L i 1 . 3 1Mn0 . 6 3Mo0 . 0 6O2 ,Li1.29Mn0.57Mo0.14O2, and Li1.25Mn0.5Mo0.25O2, respectively).All samples exhibit characteristic XRD patterns of a disorderedrocksalt-type structure, in which reflections can be indexed as111, 200, 220, 311, and 222 in the cubic rocksalt lattice. Thelattice constant increases with increasing Mo content,calculated as 4.07 Å, 4.09 Å, 4.13 Å, and 4.18 Å for x = 0,0.1, 0.25, and 0.5, respectively (Table S1 and Figures S3−S6).Transmission electron microscopy (TEM) and energydispersive X-ray spectroscopy (EDS) analyses are performedon Li1.34Mn0.66O2 and Li1.25Mn0.5Mo0.25O2, as representativecompositions (Figure 2). Elemental mapping reveals aFigure 1. XRD patterns of 3/2Li4/3Mn2/3O2-xLiMoO2 compoundswith x = 0, 0.1, 0.25 and 0.5.Figure 2. TEM images of (a) Li1.33Mn0.67O2 (x = 0) and (c)Li1.25Mn0.5Mo0.25O2 (x = 0.5), with corresponding elementalmappings for (b) Mn in Li1.33Mn0.67O2 and (d−e) Mn and Mo inLi1.25Mn0.5Mo0.25O2.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875580https://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig2&ref=pdfpubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashomogeneous distribution of Mn and Mo, confirming theformation of solid-solution disordered rocksalt oxides. Allsamples consist of irregularly shaped particles with sizesranging between 200 nm and 1 μm (Figure S7).Figure 3 shows the O K-edge, Mn L-edge, and Mo L-edgeEELS spectra for 3/2Li4/3Mn2/3O2-xLiMoO2 compounds withx = 0, 0.1, 0.25, and 0.5. Figure 3b shows that the increasingvalue of x shifts the Mn L-edge peak to lower energies. Thisshift indicates that manganese is reduced with higher levels ofMo doping. On the other hand, the Mo-L-edge spectra for allcompositions in Figure 3c resemble that of MoO3, indicatingthat Mo in the 3/2Li4/3Mn2/3O2-xLiMoO2 compounds ishexavalent. These findings reveal that during the synthesisprocess molybdenum is oxidized from the trivalent state inLiMoO2 to a hexavalent state, while manganese is reducedfrom the tetravalent state in Li2MnO3 to a lower oxidationstate according to the Mo content in the compound.Considering a three-electron transfer per Mo atom (Mo3+ →Mo6+ + 3e−), the expected average oxidation states in 3/2Li4/3Mn2/3O2-xLiMoO2 compounds with x = 0, 0.1, 0.25, and0 . 5 a r e e s t i m a t e d t o b e L i 1 . 3 3M n 0 . 6 74 + O 2 ,Li1.31Mn0.633.7+Mo0.066+O2, Li1.29Mn0.573.3+Mo0.146+O2, andLi1.25Mn0.52.5+Mo0.256+O2.Figure 4 shows the 7Li NMR spectra for 3/2Li4/3Mn2/3O2-xLiMoO2 compounds with x = 0, 0.1, 0.25, and 0.5, providinginsight into the evolution of the local lithium environmentsupon Mo incorporation. The spectrum of Li4/3Mn2/3O2 (x =0) exhibits a very broad and significantly shifted 7Li resonance,which is a characteristic of Mn-based cation-disorderedrocksalt structures. The large spectral width reflects thebroad distribution of Li environments inherent to thedisordered cation lattice, where Li nuclei experience a rangeof hyperfine interactions with neighboring paramagnetic Mnions, together with fast relaxation typical of paramagneticsystems.12,13 Upon Mo incorporation, the center of this broadresonance progressively shifts toward lower ppm values,moving from approximately 520.3 ppm in x = 0 to about291 ppm in x = 0.5 (Figure S8e). This shift reflects a change inthe average magnetic environment surrounding Li and isconsistent with the reduction of the average Mn oxidationstate. In addition to this systematic shift, a much narrowerresonance centered at 130.5 ppm emerges, with its intensityincreasing with higher Mo content (Figures 4 and S8f). Theappearance of this signal indicates the formation of a distinctlocal Li environment associated with the Mo incorporation.The narrower line width of this peak is consistent with Li siteslocated near diamagnetic Mo6+ centers and suggests theformation of preferred Mo-containing local configurations.HRTEM observations in Li1.29Mn0.57Mo0.14O2 (x = 0.25) as arepresentative composition (Figure S9) reveal a continuouscrystalline lattice, with no indication of secondary phaseformation. These results suggest that such Mo-containing localconfigurations correspond to locally favored cation arrange-ments embedded within the disordered rocksalt lattice.To further examine the effects of Mo6+ incorporation on Li+migration, the migration energy barrier for a single-vacancymechanism is estimated by the DFT nudged elastic band(NEB) method for representative local pathways inLi1.31Mn0.63Mo0.06O2 and Li1.25Mn0.5Mo0.25O2 (Figure S10).The calculated forward (backward) migration barriers are 0.76(0.20) and 0.87 (0.70) eV, respectively. These values arecomparable in magnitude, suggesting that representative localLi+ migration barriers remain broadly similar to Moincorporation.To elucidate how the Mo-induced modification of Mnoxidation states influences electrochemical behavior, theelectrochemical performance of 3/2Li4/3Mn2/3O2-xLiMoO2compounds (x = 0, 0.1, 0.25, and 0.5) is investigated insolid-state batteries. Solid-state cells are employed to suppresstransition metal dissolution commonly observed in liquidelectrolytes,14 which could otherwise obscure the intrinsicredox chemistry of Mn-based disordered oxides. Figure 5a−dcompares the charge−discharge voltage profiles over 20 cyclesof 3/2Li4/3Mn2/3O2-xLiMoO2 compounds with x = 0, 0.1,0.25, and 0.5, respectively. Figure 5e depicts the dischargecapacity of all compounds as a function of cycle number,elucidating a trend of higher capacity retention with increasingMo content. Although the average operating voltage variesFigure 3. (a) O K-edge, (b) Mn L-edge, and (c) Mo L-edge EELSspectra for 3/2Li4/3Mn2/3O2-xLiMoO2 compounds with x = 0, 0.1,0 .25 , and 0 .5 (L i 1 . 3 3Mn0 . 6 7O2 , L i 1 . 3 1Mn0 . 6 3Mo0 . 0 6O2 ,Li1.29Mn0.57Mo0.14O2, and Li1.25Mn0.5Mo0.25O2, respectively). EELSspectra of Li2MnO3, LiMoO2, Mn2O3, and MoO3 precursors areshown for comparison.Figure 4. 7Li MAS NMR spectra of 3/2Li4/3Mn2/3O2-xLiMoO2compounds with x = 0, 0.1, 0.25, and 0.5. Asterisks (*) indicatespinning sidebands.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875581https://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig4&ref=pdfpubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asslightly among the compounds (Figure S11), the improvedcapacity retention leads to superior energy density duringcycling, as shown in Figure 5f.To gain deeper insight into the Mo-induced changes in theelectronic structure and their impact on redox behavior, first-principles DFT calculations are performed to analyze theelectronic density of states (DOS) and oxidation stateevolution (by Bader charge analysis) in Li1.33Mn0.67O2 (x =0) and Li1.25Mn0.5Mo0.25O2 (x = 0.5) as representativecompositions. Figure 6 presents the Bader charge (QBader)distributions of transition metal and oxygen atoms inLi1.33Mn0.67O2 and Li1.25Mn0.5Mo0.25O2, using Li20Mn11O32and Li20Mn8Mo4O32 supercells with random configurationsof Li−Mn−Mo-vacancy arrangements, as model structures,respectively. In Li20Mn11O32, the QBader,Mn distribution, lowerand upper bounds (lBader,Mn, uBader,Mn), are determined to be+1.83e and +1.97e, respectively (Figure 6a, n = 20), thesevalues are close to that in P42/mnm MnO2 (average QBader,Mn)= +2.00e, see Table S2 for the reference compounds andsuggest a dominantly oxidized state in the form of Mn4+. Thecorresponding O Bader charge parameters lBader,O and uBader,Ovalues are −1.26e and −1.11e, respectively (Figure 6c, n = 20).In contrast, Mo incorporation in Li20Mn8Mo4O32 leads to apronounced downshift of Mn Bader charges, with lBader,Mn anduBader,Mn values decreased to +1.69e and +1.70e, respectively(Figure 6b, n = 0), comparable to that in PcabMn2O3 (averageQBader,Mn = +1.78e), which indicates a reduced oxidation stateclose to Mn3+. lBader,Mo and uBader,Mo values are both +2.51e(Figure 6e, n = 0), approaching that of Pnma MoO3 (averageQBader,Mo = +2.84e) and hinting at a Mo oxidation state closerto 6+. The corresponding lBader,O and uBader,O values are −1.35eand −1.25e, respectively (Figure 6d, n = 0). Here, the overalldownshift in QBader,Mn and QBader,O values in Li20Mn8Mo4O32relative to Li20Mn11O32 demonstrates that Mo incorporationredistributes electronic charge from Mo to Mn and O,consistent with the experimentally observed redox tendency(Figure 3). The experimentally inferred average Mn oxidationstate of +2.5, which indicates the presence of Mn2+ inLinMn8Mo4O32, is, however, not apparent in the presentcalculation result. Small quantitative differences may arisebecause the present supercell model assumes a randomLi−Mn−Mo distribution and therefore does not fully captureFigure 5. (a−d) Charge and discharge curves of 3/2Li4/3Mn2/3O2-xLiMoO2 compounds with x = 0, 0.1, 0.25, and 0.5 (Li1.33Mn0.67O2,Li1.31Mn0.63Mo0.06O2, Li1.29Mn0.57Mo0.14O2 and Li1.25Mn0.5Mo0.25O2, respectively). (e) Discharge capacity and (f) discharge energy as a function ofcycle number. Measurements are performed in solid-state cells employing an argyrodite-type solid electrolyte and a Li−In counter electrode at 50°C.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875582https://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig5&ref=pdfpubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asthe preferred local cation configurations indicated experimen-tally (Figure 4). In addition, inherent limitations of Badercharge analysis, such as the tendency to overestimate the ionicnature of bonds, should also be considered. Figures S12a andS13a show the electronic DOS profiles of Li1.33Mn0.67O2 andLi1.25Mn0.5Mo0.25O2 structures, respectively. In the prechargestate, nonbonding O 2p states contribute significantly to thehighest occupied states in Li1.33Mn0.67O2 (Figure S12a),implying potential oxygen redox activity upon cycling. Incontrast, the contribution of the O 2p states to the highestoccupied states is considerably reduced in Li1.25Mn0.5Mo0.25O2(Figure S13a).The evolution of Bader charges upon delithiation furtherreveals a qualitative change in the charge-compensationmechanism. For LinMn11O32, the main contribution to thecapacity is shown to be coming from oxygen oxidation, asevidenced by the QBader,O distribution, which becomesprogressively less negative as n decreases (Figure 6c). Theconcurrent increase in the distribution width of QBader,O alsoreflects the pronounced oxygen oxidation activity in thestructure. In contrast, there is only minimal change vs n for Mnatoms (Figure 6a), with QBader,Mn values remaining largelyunchanged even up to full-Li deintercalation (n = 20). Thesetrends are consistent with the electronic DOS profiles (FigureS12), in which as n decreases, the O 2p states are increasinglyFigure 6. DFT-based Bader charge (QBader) distributions of transition metal and oxygen atoms in LinMn11O32 and LinMn8Mo4O32 supercell modelstructures, respectively, with n = 20 as the precharged state. (a, c) QBader distributions for Mn and O, respectively, in LinMn11O32. (b, d, e) QBaderdistributions for Mn, O, and Mo, respectively, in LinMn8Mo4O32.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875583https://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig6&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig6&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig6&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig6&ref=pdfpubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asup-shifted in energy, while the Mn electronic structure hardlychanges. On the other hand, for the LinMn8Mo4O32 structure,the capacity is contributed by the initially reduced Mn3+, asshown by QBader,Mn values becoming more positive as nincreases (Figure 6b). Meanwhile, the extent of the QBader,Ochange vs n (Figure 6d) is shown to be significantly less thanthat in LinMn11O32 (Figure 6c), indicating suppressed O redoxactivity. It is pointed out that the Mo atoms have QBader,Movalues that are relatively invariant and remain close to anoxidation state of 6+ as n decreases. The correspondingelectronic DOS profiles for Mn, O, and Mo support theaforementioned Bader charge analysis results (Figure S13). Inparticular, up to n = 10, the Mn DOS profiles reveal a trend inwhich Mn-3d states below the Fermi level become increasinglylifted up in energy with decreasing n, while the O and Mo DOSprofiles only show a relatively minimal change. For low valuesof n (n < 10), the charge-compensation mechanism alsoinvolves the participation of O oxidation (Figure S13).Complementary analyses of Mn/Mo−O bond lengths andMn/Mo magnetic moments (Table S3) further support theBader charge analysis, indicating that Mn is in a more reducedstate in LinMn8Mo4O32 and becomes strongly involved incharge compensation during delithiation, while Mo remains ina relatively highly oxidized state.To experimentally validate the DFT-predicted charge-compensation mechanism, O K-edge, Mn L-edge, and Mo L-edge EELS spectra are collected for Li1.25Mn0.5Mo0.25O2 atdifferent states of charge (SOC) during the first cycle (Figure7a−c). Figure 7d shows the first cycle voltage profile ofLi1.25Mn0.5Mo0.25O2, indicating the SOC points (i−v) at whichEELS measurements are performed. Upon the first charge to4.2 V vs Li, the Mn L-edge peak (Figure 7b) shifts from anenergy lower than that of Mn2O3, which is used as a standardfor Mn3+, to a higher energy similar to that of Mn4+ in layeredLi2MnO3. After discharge to 1.5 V vs Li, the Mn L-edge peakreturns almost to the original position. This indicates thatMn2.5+ (oxidation state estimated from the electron transferfrom Mo to Mn) is oxidized to Mn4+ during the initial chargeand subsequently reduced back to an oxidation state nearMn2.5+ during the discharge. Consistent behavior is alsoobserved in the Mn L-edge XANES (X-ray near-edge structure,Figure S14), confirming the reversibility of the Mn redoxprocess. In contrast, the Mo L-edge energy remains similar tothat in MoO3 throughout the charge and discharge (Figure7c), indicating that molybdenum does not participate in theredox reaction through the charge and discharge. These resultsare in good agreement with results from the Bader chargeanalysis (Figure 6) and demonstrate that the chargecompensation in the Li1.25Mn0.5Mo0.25O2 compound ispredominantly governed by the oxidation and reduction ofmanganese, with no contribution from molybdenum.In contrast to Li1.25Mn0.5Mo0.25O2, the Mn L EELS spectraof Li1.33Mn0.67O2 collected at different states of charge (FigureS15) do not show a clear shift toward higher energy, indicatingthat Mn is not the dominant charge-compensation speciesduring charge. A similar behavior in the Mn EELS spectra hasbeen reported for layered Li1.33Mn0.67O215 and has beenassociated with oxygen charge compensation and oxygen loss.Consistently, online mass spectroscopy (Figure S16) showsthat oxygen gas evolution begins at an early state of charge(∼168 mAh/g). These results suggest that charge compensa-tion in Li1.33Mn0.67O2 has a major oxygen contribution, inagreement with the Bader charge analysis and is accompaniedby oxygen loss. This oxygen-deficient charged state may alsocontribute to the excess lithium insertion observed duringdischarge (Figure S15c), possibly through defect environmentsgenerated by oxygen loss.Table 1 summarizes the nominal composition of 3/2Li4/3Mn2/3O2-xLiMoO2 compounds, together with theestimated oxidation states of the transition metals, thetheoretical capacities based on the Li reservoir and Mnredox, the experimental first charge capacities, the calculatedMn redox contribution, and the capacity retentions relative tothe third cycle. Increasing x progressively shifts the chargecompensation from oxygen redox to Mn redox. However, forall compositions, the practical charge capacity exceeds thetheoretical value expected from the Mn redox alone. Badercharge analysis suggests that this extra capacity arises from theoxygen redox activity. Although the oxygen redox contributionprogressively diminishes with increasing Mo content, capacityretentions remain similar for x = 0, x = 0.1, and x = 0.25(75.1%, 77.2%, and 77.7%, respectively), while a markedimprovement is observed for x = 0.5 (99.7%). These resultssuggest that, among the compositions studied, the reduction inoxygen redox becomes sufficient only at x = 0.5 to substantiallymitigate the degradation process, resulting in a distinct andmore stable cycling regime. Figure 8 shows the online massspectroscopy (MS) analysis conducted on a solid-state cellusing Li1.25Mn0.5Mo0.25O2 (x = 0.5) during the first cycle atroom temperature. No gas evolution is detected forLi1.25Mn0.5Mo0.25O2, even as the charge progressed up to 250mAh/g (with the diminishing oxygen background coming fromthe carrier gas). These results further confirm thatFigure 7. (a) O K-edge, (b) Mn L-edge, and (c) Mo L-edge EELSspectra of samples obtained from cells using Li1.25Mn0.5Mo0.25O2 (x =0.5) cycled at different states of charge (SOC) over the first cycle. (d)First-cycle voltage charge−discharge curves indicating the selectedSOC points i, ii, iii, iv, and v.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875584https://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig7&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig7&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig7&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig7&ref=pdfpubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asmolybdenum incorporation shifts the charge-compensationmechanism toward manganese-centered redox processes bystabilizing Mn at lower oxidation states. As a consequence, thecontribution of oxygen redox is minimized, leading to theeffective suppression of gas evolution for x = 0.5 (Figure 8).Molybdenum incorporation, therefore, emerges as an effectivestrategy for simultaneously modulating the electronic structureand lithium stoichiometry in Mn-based disordered rocksaltoxides. By lowering the average Mn oxidation state to trivalentor lower while maintaining a high lithium content in thestructure, Mo doping enables a predominantly Mn-basedcharge-compensation mechanism without sacrificing thelithium excess. According to the lithium percolation theory,16increased lithium excess enhances lithium-ion percolation,thereby enabling higher capacities. This combination of highlithium excess and a low oxidation state in manganese thusunderpins both high capacity (exceeding that of previouslyreported Mn-based disordered rocksalt materials such asLiMnO2 and Li1.05Mn0.85Ti0.1O2, Figures S17−S19) andimproved cyclability, owing to minimized contribution ofoxygen redox in the electrode reaction.The electrochemical performance of Li1.25Mn0.5Mo0.25O2 isfurther investigated under increased cathode mass-loadingconditions in the solid-state battery. Figure 9 shows thecharge−discharge voltage profiles and cycling performance ofsolid-state cells with composite cathode mass loadings of 10.2mg/cm2 and 20.4 mg/cm2, cycled at a C-rate of C/20(corresponding to current densities of 0.06 mA/cm2 and 0.13mA/cm2, respectively). Even at elevated mass loading,Li1.25Mn0.5Mo0.25O2 demonstrates a high discharge capacityexceeding 300 mAh/g and relatively high-capacity retentionafter 50 cycles of 91.4% and 85.8% (relative to the 10th cycle)for mass loadings of 10.2 mg/cm2 and 20.4 mg/cm2,respectively. While a promising cathode material for solid-state batteries, the applicability of Li1.25Mn0.5Mo0.25O2 toconventional liquid-electrolyte cells is also demonstrated(Figure S20). In liquid-electrolyte Li-ion cells using LiFSI inDMC, Li1.25Mn0.5Mo0.25O2 delivers a discharge capacityapproaching its theoretical value (363.6 mAh/g), an initialdischarge energy density of 955 Wh/kg, and an energy densityretention of 96% after 50 cycles.■ CONCLUSIONSMn-based cation-disordered rocksalt oxides in the solid-solution system 3/2Li4/3Mn2/3O2-xLiMoO2 (x = 0, 0.1, 0.25,and 0.5) have been synthesized and systematically investigatedto elucidate the role of Mo incorporation in governing theredox chemistry and electrochemical performance. CombinedTable1.NominalCompositionsof3/2Li 4/3Mn 2/3O2-xLiMoO2Compounds,TogetherwiththeEstimatedTransitionMetalOxidationState,TheoreticalCapacitiesBasedonAvailableLi,andMnRedox,FirstChargeCapacities,CalculatedMnRedoxContribution,andCapacityRetentionsRelativetotheThirdCyclexnominalcompositiontheoreticalcapacitybasedonLi)/mAh/gtheoreticalcapacitybasedonMnredox/mAh/gfirst-chargecapacity/mAh/gMnredoxcontribution/%capacityretention/%0Li1.34Mn 0.664+O2458.90245.4075.10.1Li1.31Mn 0.6253.7+Mo 0.06256+O2431.961.7371.71777.20.25Li1.29Mn 0.573.3+Mo 0.146+O2400.6131.3292.64577.70.5Li1.25Mn 0.52.5+Mo 0.256+O2363.6218.2301.97299.7Figure 8. Gas analysis of a Li1.25Mn0.5Mo0.25O2 (x = 0.5) solid-statecell performed at room temperature (∼20 °C). The cell employed anargyrodite-type solid electrolyte and a Li−In counter electrode.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875585https://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig8&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig8&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig8&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig8&ref=pdfpubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asspectroscopic characterization and first-principles calculationsreveal that Mo incorporation lowers the average Mn oxidationstate and shifts the charge-compensation mechanism fromoxygen-centered to predominantly Mn-centered redox pro-cesses. These results establish Mo incorporation as an effectivestrategy for simultaneously controlling transition metaloxidation states, lithium stoichiometry, and redox pathwaysin Mn-based disordered oxides. More broadly, the presentstudy highlights compositional and electronic structureengineering as a powerful design principle for tuning redoxchemistry in cation-disordered oxides and advancing thedevelopment of high-capacity Mn-based cathode materialswith superior cyclability.■ ASSOCIATED CONTENT*sı Supporting InformationThe Supporting Information is available free of charge athttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304.XRD patterns of Li2MnO3 (Li4/3Mn2/3O2), and LiMoO2precursors, and of Li1.25Mn0.5Mo0.25O2 sample after 30,60, and 90 h of ball-milling (Figure S1). Schematicillustration of the battery prototype (Figure S2). Le Bailrefinement results for the XRD pattern of 3/2Li4/3Mn2/3O2-xLiMoO2 compounds (Table S1 andFigures S3−S6). SEM images of 3/2Li4/3Mn2/3O2-xLiMoO2 compounds (Figure S7). Gaussian fit of the7Li MAS NMR spectra of 3/2Li4/3Mn2/3O2-xLiMoO2compounds (Figure S8). HRTEM image ofLi1.29Mn0.57Mo0.14O2 (x = 0.25, Figure S9). Li+ migrationenergy profile for single-vacancy mechanism by the DFTnudged elastic band (NEB) method for Li1.33Mn0.67O2and Li1.25Mn0.5Mo0.25O2 (Figure S10). Dischargeweighted average voltage energy as a function of cyclenumber of 3/2Li4/3Mn2/3O2-xLiMoO2 compounds(Figure S11). DFT-calculated average Bader chargesand corresponding assigned oxidation states of transitionmetal and oxygen atoms in selected reference Mn- andMo-based oxides (Table S2). DFT-calculated electronicdensity of states (DOS) at different stages of charge (n)for the LinMn11O32 and LinMn8Mo4O32 supercell modelstructures (Figures S12 and S13). DFT-calculated bondlengths and magnetic moments at different state-of-charge levels n in LinMn11O32 and LinMn8Mo4O32,together with reference compounds (Table S3). Mn L-edge XANES spectra of Li1.25Mn0.5Mo0.25O2 (FigureS14). O K-edge, and Mn L-edge EELS spectra ofsamples obtained from Li1.33Mn0.67O2 (x = 0) cycled atdifferent states of charge (SOC) over the first cycle(Figure S15). Gas analysis of a solid-state cell usingLi1.33Mn0.67O2 (x = 0, Figure S16). XRD pattern andSEM image of LiMnO2 (Figure S17). XRD patterns andSEM images of Li1.05Mn0.85Ti0.1O2 (Figure S18).Electrochemical performance of Li1.25Mn0.5Mo0.25O2compared to LiMnO2, and Li1.05Mn0.85Ti0.1O2 (FigureS 1 9 ) . E l e c t r o c h em i c a l p e r f o r m a n c e o fLi1.25Mn0.5Mo0.25O2 in liquid-electrolyte cells (FigureS20) (PDF)■ AUTHOR INFORMATIONCorresponding AuthorMarcela Calpa − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0003-4934-4595; Email: calpa.marcela@nims.go.jpAuthorsRandy Jalem − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0001-9505-771XFigure 9. (a, b) Charge and discharge curves of Li1.25Mn0.5Mo0.25O2 solid-state cells with composite cathode mass loadings of (a) 10.2 mg/cm2 and(b) 20.4 mg/cm2, and (c) the corresponding discharge capacity as a function of cycle number. Measurements are performed in all-solid-state cellsemploying an argyrodite-type solid electrolyte and a Li−In counter electrode at 50 °C.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875586https://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?goto=supporting-infohttps://pubs.acs.org/doi/suppl/10.1021/acs.chemmater.6c00304/suppl_file/cm6c00304_si_001.pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Marcela+Calpa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0003-4934-4595https://orcid.org/0000-0003-4934-4595mailto:calpa.marcela@nims.go.jphttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Randy+Jalem"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0001-9505-771Xhttps://orcid.org/0000-0001-9505-771Xhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Taiga+Ozawa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig9&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig9&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig9&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?fig=fig9&ref=pdfpubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asTaiga Ozawa − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, JapanMinako Nishioka − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, JapanAnna Myojin − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, JapanGen Hasegawa − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0002-9297-6902Naoaki Kuwata − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0002-0736-6967Shoichi Matsuda − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; NIMS-SoftBankAdvanced Technologies Development Center, NationalInstitute for Material Science, Tsukuba, Ibaraki 305-0044,Japan; orcid.org/0000-0002-0640-3404Kei Kubota − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0001-8941-3650Kazunori Takada − Center for Green Research on Energy andEnvironmental Science, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; NIMS-SoftBankAdvanced Technologies Development Center, NationalInstitute for Material Science, Tsukuba, Ibaraki 305-0044,Japan; orcid.org/0000-0001-7568-1806Complete contact information is available at:https://pubs.acs.org/10.1021/acs.chemmater.6c00304NotesThe authors declare no competing financial interest.■ ACKNOWLEDGMENTSA part of this work was carried out at the NIMS-SoftBankAdvanced Technologies Development Center as a jointresearch between NIMS and SoftBank Corp. They alsoacknowledge the NIMS Battery Platform for its technicalsupport on SEM and TEM measurements. R.J. is thankful forthe support in part by JST through Green Technologies ofExcellence (GteX) grant number JPMJGX23S2, JSPSKAKENHI grant number JP21K14729, and by MEXT asMaterials Processing Science project (“Materealize”) grantnumber JPMXP0219207397. The calculations were performedon the supercomputer at NIMS (Numerical MaterialsSimulator) and the supercomputer Fugaku at RIKEN throughthe HPCI System Research Project (project ID: hp240118 andhp210105).■ REFERENCES(1) Lun, Z.; Ouyang, B.; Kwon, D.-H.; Ha, Y.; Foley, E. E.; Huang,T.-Y.; Cai, Z.; Kim, H.; Balasubramanian, M.; Sun, Y.; et al. Cation-disordered rocksalt-type high-entropy cathodes for Li-ion batteries.Nat. Mater. 2021, 20 (2), 214−221.(2) Seo, D.-H.; Lee, J.; Urban, A.; Malik, R.; Kang, S.; Ceder, G. Thestructural and chemical origin of the oxygen redox activity in layeredand cation-disordered Li-excess cathode materials. Nat. Chem. 2016, 8(7), 692−697.(3) Sharpe, R.; House, R. A.; Clarke, M. J.; Förstermann, D.; Marie,J.-J.; Cibin, G.; Zhou, K.-J.; Playford, H. Y.; Bruce, P. G.; Islam, M. S.Redox chemistry and the role of trapped molecular O2 in Li-richdisordered rocksalt oxyfluoride cathodes. J. Am. Chem. Soc. 2020, 142(52), 21799−21809.(4) Kataoka, R.; Kojima, T.; Takeichi, N. Electrochemical propertyof Li-Mn cation disordered Li-Rich Li2MnO3 with NaCl typestructure. J. Electrochem. Soc. 2018, 165 (2), A291−A296.(5) Li, H.; Fong, R.; Woo, M.; Ahmed, H.; Seo, D.-H.; Malik, R.;Lee, J. Toward high-energy Mn-based disordered-rocksalt Li-ioncathodes. Joule 2022, 6 (1), 53−91.(6) Calpa, M.; Kubota, K.; Mizuki, E.; Ono, M.; Matsuda, S.;Takada, K. Voltage hysteresis hidden in an asymmetric reactionpathway. Energy Storage Mater. 2023, 63, No. 103051.(7) (a) Kresse, G. Ab initio molecular dynamics for liquid metals. J.Non-Cryst. Solids 1995, 192-193, 222−229. (b) Kresse, G.;Furthmüller, J. Efficient iterative schemes for ab initio total-energycalculations using a plane-wave basis set. Phys. Rev. B 1996, 54 (16),No. 11169.(8) Tu, X. Y.; Shu, K. X-ray diffraction study on phase transition oforthorhombic LiMnO2 in electrochemical conversions. J. Solid StateElectrochem. 2008, 12 (3), 245−249.(9) Anisimov, V. I.; Zaanen, J.; Andersen, O. K. Band theory andMott insulators: Hubbard U instead of Stoner I. Phys. Rev. B 1991, 44(3), No. 943.(10) (a) Coquet, R.; Willock, D. J. The (010) surface of α-MoO3, aDFT+ U study. Phys. Chem. Chem. Phys. 2005, 7 (22), 3819−3828.(b) Zhou, F.; Cococcioni, M.; Marianetti, C. A.; Morgan, D.; Ceder,G. First-principles prediction of redox potentials in transition-metalcompounds with LDA+ U. Phys. Rev. B:Condens. Matter Mater. Phys.2004, 70 (23), No. 235121.(11) Klimes,̌ J.; Bowler, D. R.; Michaelides, A. Chemical accuracy forthe van der Waals density functional. J. Phys.: Condens. Matter 2010,22 (2), No. 022201.(12) Pecher, O.; Carretero-González, J.; Griffith, K. J.; Grey, C. P.Materials’ methods: NMR in battery research. Chem. Mater. 2017, 29(1), 213−242.(13) Lee, J.; Kitchaev, D. A.; Kwon, D.-H.; Lee, C.-W.; Papp, J. K.;Liu, Y.-S.; Lun, Z.; Clément, R. J.; Shi, T.; McCloskey, B. D.; et al.Reversible Mn2+/Mn4+ double redox in lithium-excess cathodematerials. Nature 2018, 556 (7700), 185−190.(14) Zhan, C.; Wu, T.; Lu, J.; Amine, K. Dissolution, migration, anddeposition of transition metal ions in Li-ion batteries exemplified byMn-based cathodes−a critical review. Energy Environ. Sci. 2018, 11(2), 243−257.(15) Oishi, M.; Shimoda, K.; Ohara, K.; Kabutan, D.; Kawaguchi, T.;Uchimoto, Y. Disordered cubic spinel structure in the delithiatedLi2MnO3 revealed by difference pair distribution function analysis. J.Phys. Chem. C 2020, 124 (44), 24081−24089.(16) Lun, Z.; Ouyang, B.; Cai, Z.; Clément, R. J.; Kwon, D.-H.;Huang, J.; Papp, J. K.; Balasubramanian, M.; Tian, Y.; McCloskey, B.D.; et al. Design principles for high-capacity Mn-based cation-disordered rocksalt cathodes. Chem 2020, 6 (1), 153−168.Chemistry of Materials pubs.acs.org/cm Articlehttps://doi.org/10.1021/acs.chemmater.6c00304Chem. Mater. 2026, 38, 5579−55875587https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Minako+Nishioka"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Anna+Myojin"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Gen+Hasegawa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0002-9297-6902https://orcid.org/0000-0002-9297-6902https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Naoaki+Kuwata"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0002-0736-6967https://orcid.org/0000-0002-0736-6967https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Shoichi+Matsuda"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0002-0640-3404https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Kei+Kubota"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0001-8941-3650https://orcid.org/0000-0001-8941-3650https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Kazunori+Takada"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0001-7568-1806https://pubs.acs.org/doi/10.1021/acs.chemmater.6c00304?ref=pdfhttps://doi.org/10.1038/s41563-020-00816-0https://doi.org/10.1038/s41563-020-00816-0https://doi.org/10.1038/nchem.2524https://doi.org/10.1038/nchem.2524https://doi.org/10.1038/nchem.2524https://doi.org/10.1021/jacs.0c10270?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/jacs.0c10270?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1149/2.1041802jeshttps://doi.org/10.1149/2.1041802jeshttps://doi.org/10.1149/2.1041802jeshttps://doi.org/10.1016/j.joule.2021.11.005https://doi.org/10.1016/j.joule.2021.11.005https://doi.org/10.1016/j.ensm.2023.103051https://doi.org/10.1016/j.ensm.2023.103051https://doi.org/10.1016/0022-3093(95)00355-Xhttps://doi.org/10.1103/PhysRevB.54.11169https://doi.org/10.1103/PhysRevB.54.11169https://doi.org/10.1007/s10008-007-0384-3https://doi.org/10.1007/s10008-007-0384-3https://doi.org/10.1103/PhysRevB.44.943https://doi.org/10.1103/PhysRevB.44.943https://doi.org/10.1039/b511044khttps://doi.org/10.1039/b511044khttps://doi.org/10.1103/PhysRevB.70.235121https://doi.org/10.1103/PhysRevB.70.235121https://doi.org/10.1088/0953-8984/22/2/022201https://doi.org/10.1088/0953-8984/22/2/022201https://doi.org/10.1021/acs.chemmater.6b03183?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1038/s41586-018-0015-4https://doi.org/10.1038/s41586-018-0015-4https://doi.org/10.1039/C7EE03122Jhttps://doi.org/10.1039/C7EE03122Jhttps://doi.org/10.1039/C7EE03122Jhttps://doi.org/10.1021/acs.jpcc.0c07124?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.jpcc.0c07124?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1016/j.chempr.2019.10.001https://doi.org/10.1016/j.chempr.2019.10.001pubs.acs.org/cm?ref=pdfhttps://doi.org/10.1021/acs.chemmater.6c00304?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as