# Fileset

[ise260499_program book page 44_KJD abstract.pdf](https://mdr.nims.go.jp/filesets/cdca1a3a-6ab1-4ce2-ba55-53a776e29934/download)

## Creator

[Jedeok Kim](https://orcid.org/0000-0003-4301-1044)

## Rights

[In Copyright](http://rightsstatements.org/vocab/InC/1.0/)

## Other metadata

[Ce-dope Effect of Crosslinked Membranes using Highly Sulfonated Polyphenylsulfone (PPSU) Ionomers](https://mdr.nims.go.jp/datasets/945c63d6-c882-4cb1-adbb-b9675657e45e)

## Fulltext

Ce-dope Effect of Crosslinked Membranes using Highly Sulfonated Polyphenylsulfone (PPSU) Ionomers Je-Deok Kim Environmental Circulation Composite Materials Group, Functional Materials Field, Research Center for Electronic and Optical Materials National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan Kim.Jedeok@nims.go.jp Aiming to achieve carbon neutrality by 2050, research into CO2 utilization for energy generation is gaining momentum. Furthermore, research into alternative materials is required due to PFAS (Per-and poly-fluoroalkyl substances) regulations. We are conducting research into the application of SPPSU (Sulfonated Polyphenylsulfone) ionomer electrolyte membranes as a non-fluorinated electrolyte with the aim of contributing to a carbon-neutral society [1]. SPPSU ionomers are used as electrolyte membranes for fuel cells, water electrolysis, RFBs, and electrolysis of organic and inorganic materials [1]. In this study, we prepared a crosslinked electrolyte membrane (CSPPSU: Crosslinked Sulfonated Polyphenylsulfone) using an ionomer with two sulfonic acid groups per PPSU unit (SPPSU(2S)), and report on the physical and chemical properties and fuel cell performance of the Ce-dope and Fenton test membranes. The synthesis of SPPSU(2S) ionomer and the membrane preparation process for the crosslinked membrane have been reported previously [1]. Ce-dope and Fenton test methods were also performed using references [2]. The stability of the CSPPSU membrane and the Ce-doped CSPPSU membrane was examined at 80°C for 2 h using a Fenton solution (3% H2O2 + 2 ppm Fe). Table 1 shows the results of the water uptake (WU, %), ion exchange capacity (IEC, meq/g), flexural modulus (Mpa) from stress-strain measurements, electrical conductivity, and fuel cell properties for the CSPPSU membrane, the Ce-doped CSPPSU membrane, and the Ce-doped CSPPSU membrane after the Fenton test. The membrane maintained its flexibility even after the Fenton test, confirming that Ce-doping improved the chemical stability of the CSPPSU membrane against the Fenton solution. Ce-doping increased the IEC and WU of the CSPPSU membrane, but its mechanical properties became slightly more rigid. Furthermore, conductivity measurements at 80°C and with varying relative humidity (RH) showed that Ce-doping of the CSPPSU membrane reduced its conductivity by approximately 13% compared to before Ce-doping. After the Fenton test, a further 39% decrease in conductivity was observed. Single fuel cell evaluation was performed using these membranes. Comparing the voltage and resistivity of the CSPPSU membrane, the Ce-doped CSPPSU membrane, and the Ce-doped CSPPSU membrane after the Fenton test at a cell temperature of 80°C, RH 100%, and a current density of 0.5 A/cm2, the differences before and after Ce-doping were nearly identical. However, cell characteristics using membranes after the Fenton test showed a decrease in voltage and an increase in resistivity. These experimental results showed that Ce-doping of the CSPPSU membrane improved its resistance to Fenton. Table 1. Properties of CSPPSU, Ce-doped CSPPSU, and Ce-doped CSPPSU membranes after Fenton test. CSPPSU membrane CSPPSU membrane Ce-doped CSPPSU Fenton tested Ce- doped CSPPSU IEC (meq/g) 3.3 4.8 3.4 WUswell (%) 74 229 345 Flexural modulus (Mpa) 803 949 956 Conductivity, (80℃, 80% RH, mS/cm) 31 27 19 IV (80℃/80℃/80℃, 100% RH) at 0.5 A/cm2 Voltage (V) 0.569 0.579 0.530 Resistivity (mohm cm2) 348 349 353 *Lab NR212 membrane measurement data; conductivity, 80℃, 80% RH: 31 mS/cm; single cell test, 80℃, 100% RH: 0.64 V, 245 mohm cm2 at 0.5 A/cm2.  Reference [1] J. Kim, 25th Topical Meeting of the International Society of Electrochemisty, Toledo, Spain, 12 – 15/May, 2019, Program book p. 13; J. Kim, 25th Topical Meeting of the International Society of Electrochemisty, Toledo, Spain, 12 – 15/May, 2019, Program book p. 49; J. Kim etal., membranes, DOI: 10.3390/membranes10020031, 2020, 10, 31-44; J. Kim, etal,; Japan patent no. 6548176, EU patent no. EP3340350, US patentno. US1086215; J.Kim, A. Ohira, membranes, DOI: 10.3390/membranes11050330, 2021, 11, 330-342; J.Kim, etal, membranes, DOI: 10.3390/membranes11110861, 2021, 11, 861-873; J. Kim, membranes, DOI: 10.3390/membranes14080173, 2024, 14, 173-184; J. Kim, Key Engineering Materials, DOI: 10.4028/p-61Ktlv, 2025, 1039, 47-52. [2] H. Lee, et al; J. Power Source, 2015, 295, 221 – 227.