# Fileset

[SI-KIB_RESb-Sb_Composite_250723ver.pdf](https://mdr.nims.go.jp/filesets/9b806f24-b169-42e2-9d51-ed29a18accc3/download)

## Creator

[Yasuhiro Domi](https://orcid.org/0000-0003-3983-2202), [Hiroyuki Usui](https://orcid.org/0000-0002-1156-0340), Naoya Wada, [Takayuki Yamamoto](https://orcid.org/0000-0003-3553-3272), [Toshiyuki Nohira](https://orcid.org/0000-0002-4053-554X), [Kei Nishikawa](https://orcid.org/0000-0002-7718-7606), [Hiroki Sakaguchi](https://orcid.org/0000-0002-4125-7182)

## Rights

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Applied Energy Materials, copyright © 2025 American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acsaem.5c02478.[In Copyright](http://rightsstatements.org/vocab/InC/1.0/)

## Other metadata

[Electrochemical Potassiation/Depotassiation Properties of Rare-Earth Antimonide/Antimony Composite Electrodes](https://mdr.nims.go.jp/datasets/1ada6171-5853-41a5-8066-fcd52d5c7d92)

## Fulltext

Template for Electronic Submission to ACS Journals 1 Supporting Information Electrochemical Potassiation/Depotassiation Properties of Rare-Earth Antimonide/Antimony Composite Electrodes Yasuhiro Domi,*,†,§ Hiroyuki Usui,†,§ Naoya Wada,‡,§ Takayuki Yamamoto,⊥ Toshiyuki Nohira,⊥ Kei Nishikawa,|| and Hiroki Sakaguchi*,†,§ †Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Minami 4–101, Koyama–cho, Tottori 680–8552, Japan ‡Course of Chemistry and Biotechnology, Department of Engineering, Graduate School of Sustainability Science, Tottori University, Minami 4–101, Koyama–cho, Tottori 680–8552, Japan §Center for Research on Green Sustainable Chemistry, Tottori University, Minami 4–101, Koyama–cho, Tottori 680–8552, Japan ⊥Institute of Advanced Energy, Kyoto University, Uji 611–0011, Japan ||International Center of Young Scientists, National Institute for Materials Science, 1–1 Namiki, Tsukuba 305–0044, Japan   2 *Corresponding Authors Yasuhiro Domi Tel/Fax: +81-857-31-5249, E-mail: domi@tottori-u.ac.jp Hiroki Sakaguchi Tel/Fax: +81-857-31-5048, E-mail: sakaguch@tottori-u.ac.jp    3       Figure S1. (a) XRD patterns of synthesized powder from Y and Sb with molar ratio of 1 : 1 by MA treatment for 10 hours and from YSb and Sb with weight ratio of 10 : 90 by MM treatment for 10 minutes. (b) SEM image and (c) particle size distribution of YSb/Sb.     4       Figure S2. (a) XRD patterns of synthesized powder from Ce and Sb with molar ratio of 1 : 1 by MA treatment for 10 hours and from CeSb and Sb with weight ratio of 10 : 90 by MM treatment for 10 minutes. (b) SEM image and (c) particle size distribution of CeSb/Sb.    5       Figure S3. (a) XRD patterns of synthesized powder from Sm and Sb with molar ratio of 1 : 1 by MA treatment for 10 hours and from SmSb and Sb with weight ratio of 10 : 90 by MM treatment for 10 minutes. (b) SEM image and (c) particle size distribution of SmSb/Sb.    6       Figure S4. (a) XRD patterns of synthesized powder from Gd and Sb with molar ratio of 1 : 1 by MA treatment for 10 hours and from GdSb and Sb with weight ratio of 10 : 90 by MM treatment for 10 minutes. (b) SEM image and (c) particle size distribution of GdSb/Sb.    7       Figure S5. TEM image of LaSb/Sb (50/50 wt.%).    8    020406080100120SbYSb/SbLaSb/SbSmSb/Sb1 M KFSA/Py13-FSA50 mA g-1CeSb/SbTheoretical capacityachievement rate / %a0204060801001200 100 200 300 400Charge-discharge cycle numberSbYSb/SbLaSb/SbSmSb/SbCeSb/SbCapacity retention / %b Figure S6. Cycle dependency of the (a) theoretical capacity achievement rate and (b) capacity retention of RESb/Sb (10/90 wt.%) composite and pure Sb electrodes.    9          0501001500 100 200 300 400Charge-discharge cycle numberSbYSbLaSbSmSb1 M KFSA/Py13-FSA50 mA g-1CeSbCapacity retention / %GdSb Figure S7. Capacity retention of pure RESb and Sb electrodes.     10  00.511.52Potential / V vs. K+/KCoulombic efficiency 1st 75.6%2nd 99.3%3rd 99.3%4th 99.1%5th 99.3%aCoulombic efficiency 1st 74.6%2nd 98.9%3rd 98.9%4th 99.0%5th 99.1%b00.511.52Potential / V vs. K+/K Coulombic efficiency 1st 72.9%2nd 98.3%3rd 98.9%4th 99.1%5th 99.3%36th 99.9%cCoulombic efficiency 1st 72.6%2nd 98.2%3rd 99.0%4th 99.0%5th 99.2%26th 99.9%d00.511.520 200 400 600Potential / V vs. K+/K Coulombic efficiency 1st 73.1%2nd 98.6%3rd 99.1%4th 99.2%5th 99.3%46th 99.9%eCapacity / mA h g-10 200 400 600Capacity / mA h g-1Coulombic efficiency 1st 70.9%2nd 98.3%3rd 98.9%4th 98.9%5th 99.2%24th 99.9%f Figure S8. Charge–discharge profiles of (a) pure Sb, (b) YSb/Sb (10/90 wt.%), (c) LaSb/Sb (10/90 wt.%), (d) CeSb/Sb (10/90 wt.%), (e) SmSb/Sb (10/90 wt.%), and (f) GdSb/Sb (10/90 wt.%) electrode in 1 M KFSA/Py13-FSA at current density of 50 mA g–1.    11  00.511.52Potential / V vs. K+/KCoulombic efficiency 1st 60.8%2nd 94.4%3rd 96.5%4th 97.5%5th 98.1%10th 99.2%aCoulombic efficiency 1st 47.8%2nd 92.1%3rd 94.3%4th 95.3%5th 96.1%24th 99.9%b00.511.52Potential / V vs. K+/KCoulombic efficiency 1st 58.0%2nd 93.6%3rd 96.1%4th 97.1%5th 97.5%46th 100%c00.511.520 100 200 300 400Potential / V vs. K+/KCapacity / mA h g-1Coulombic efficiency 1st 54.6%2nd 91.5%3rd 94.1%4th 95.7%5th 96.9%15th 100%e 0 100 200 300 400Capacity / mA h g-1Coulombic efficiency 1st 50.9%2nd 87.7%3rd 92.3%4th 95.3%5th 96.6%38th 99.9%d Figure S9. Charge–discharge profiles of (a) YSb, (b) LaSb, (c) CeSb, (d) SmSb, and (e) GdSb electrode in 1 M KFSA/Py13-FSA at current density of 50 mA g–1.    12      -0.100.1Sweep rate 0.02 mV s-1a2nd cycle-0.100.1Current density / mA cm-2b-0.0600.060 0.5 1 1.5 2cPotential / V vs. K+/K Figure S10. Cyclic voltammograms of (a) Sb, (b) YSb/Sb (10/90 wt.%), and (c) YSb electrodes.     13      -0.100.1Sweep rate 0.02 mV s-12nd cyclea-0.100.1Current density / mA cm-2b-0.05-0.02500.0250 0.5 1 1.5 2cPotential / V vs. K+/K Figure S11. Cyclic voltammograms of (a) Sb, (b) CeSb/Sb (10/90 wt.%), and (c) CeSb electrodes.     14      -0.100.1Sweep rate 0.02 mV s-12nd cyclea-0.100.1Current density / mA cm-2b-0.04-0.0200.020 0.5 1 1.5 2cPotential / V vs. K+/K Figure S12. Cyclic voltammograms of (a) Sb, (b) SmSb/Sb (10/90 wt.%), and (c) SmSb electrodes.     15      -0.100.1Sweep rate 0.02 mV s-12nd cyclea-0.0800.08Current density / mA cm-2b-0.0200.020 0.5 1 1.5 2cPotential / V vs. K+/K Figure S13. Cyclic voltammograms of (a) Sb, (b) GdSb/Sb (10/90 wt.%), and (c) GdSb electrodes.    16         Figure S14. Cross−sectional SEM image of pure Sb electrode (a) before and (b) after 50th cycle.      17         Figure S15. Cross−sectional SEM image of YSb/Sb (10/90 wt.%) electrode (a) before and (b) after 50th cycle.     18         Figure S16. Cross−sectional SEM image of GdSb/Sb (10/90 wt.%) electrode (a) before and (b) after 50th cycle.    19         Figure S17. Cross−sectional SEM image of SmSb/Sb (10/90 wt.%) electrode (a) before and after (b) 50th and (c) 100th cycles.    20         Figure S18. Cross−sectional SEM image of LaSb/Sb (10/90 wt.%) electrode (a) before and after (b) 50th, (c) 100th, (d) 125th, and (e) 150th cycles.    21         Figure S19. Cross−sectional SEM image of CeSb/Sb (10/90 wt.%) electrode (a) before and after (b) 50th, (c) 100th, (d) 125th, and (e) 150th cycles.    22      00.511.52Potential / V vs. K+ / Ka b0 50 100 150 200eTime / h0 50 100 150 20000.511.52 d0 50 100 150 200Time / hfc Figure S20. GITT curves of (a) pure Sb, (b) YSb, (c) GdSb, (d) SmSb, (e) LaSb, and (f) CeSb electrodes.    23        0.60.70.885 86 87 88 89Potential / V vs. K+ / KTime / hEEs Figure S21. Enlarged GITT curve of pure Sb electrode.    24        Table S1. Summary of lattice parameter and potassiation potential of each RESbx. Materials LaSb CeSb SmSb GdSb YSb Sb Crystal system Cubic Cubic Cubic Cubic Cubic Trigonal Lattice constant / nm 0.649 0.642 0.627 0.622 0.618 a=b=0.435 c=1.149 Volume / nm3 0.273 0.265 0.246 0.241 0.236 0.217 Potassiation potential / V vs. K+/K 0.65–0.01 0.78–0.03 0.61–0.01 0.78–0.03 0.56–0.01 0.77–0.46 0.26–0.06