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DOE OSTI · 3027525

Revealing the Roles of CuF 2 /NiF 2 Incorporation in the Electrochemical Performance of FeF 3 Cathodes in Solid‐State Batteries

Xu, Keng [Rensselaer Polytechnic Inst., Troy, NY (United States)]·Xia, Kangxuan [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000200719432)·Xiao, Ru [Rensselaer Polytechnic Inst., Troy, NY (United States)]·Grant, Ryan [Rensselaer Polytechnic Inst., Troy, NY (United States)]·Deng, Ruihao [Rensselaer Polytechnic Inst., Troy, NY (United States)]·Wu, Ruixin [Rensselaer Polytechnic Inst., Troy, NY (United States)]·Das, Ratnottam [Rensselaer Polytechnic Inst., Troy, NY (United States)]·Shao, Bowen [Rensselaer Polytechnic Inst., Troy, NY (United States)]·Hu, Enyuan [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000218814534)·Han, Fudong [Rensselaer Polytechnic Inst., Troy, NY (United States)] (ORCID:0000000325074340)
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Abstract

Mixed metal fluorides have been considered as a promising candidate to lower the voltage hysteresis of conversion-type iron fluoride cathodes, but their cycling stability is limited due to transition metal dissolution and interphase growth in liquid electrolyte batteries. Here, we study the role of incorporating CuF 2 and NiF 2 in the electrochemical performance of FeF 3 cathode in halide-based solid-state batteries to test whether we can transfer the kinetic benefit of low voltage hysteresis to solid-state batteries while using solid electrolyte to eliminate transition metal dissolution and stabilize the interphase. Synchrotron X-ray absorption spectroscopy results indicated the redox reactions are attributed to Cu 0 /Cu + and Fe 0 /Fe 2+ in 25CuF 2 -75FeF 3 and Ni 0 /Ni 2+ and Fe 0 /Fe 3+ in 10NiF 2 -90FeF 3 . While no apparent improvement in electrode kinetics can be observed, the incorporation of CuF 2 and NiF 2 can largely improve the cycling stability of FeF 3 cathodes. In conclusion, the results demonstrate the advantages of using solid-state concept to improve the cycling stability of conversion-type cathodes.

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25 ENERGY STORAGECycling stabilityIron fluoridesSolid-state batteriesVoltage hysteresisconversion cathodes

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Xu, Keng [Rensselaer Polytechnic Inst., Troy, NY (United States)], Xia, Kangxuan [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000200719432), Xiao, Ru [Rensselaer Polytechnic Inst., Troy, NY (United States)], Grant, Ryan [Rensselaer Polytechnic Inst., Troy, NY (United States)], Deng, Ruihao [Rensselaer Polytechnic Inst., Troy, NY (United States)], Wu, Ruixin [Rensselaer Polytechnic Inst., Troy, NY (United States)], Das, Ratnottam [Rensselaer Polytechnic Inst., Troy, NY (United States)], Shao, Bowen [Rensselaer Polytechnic Inst., Troy, NY (United States)], Hu, Enyuan [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000218814534), Han, Fudong [Rensselaer Polytechnic Inst., Troy, NY (United States)] (ORCID:0000000325074340). 2026-03-20. Revealing the Roles of CuF 2 /NiF 2 Incorporation in the Electrochemical Performance of FeF 3 Cathodes in Solid‐State Batteries. https://doi.org/10.1002/adfm.75027

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25 ENERGY STORAGE subjectCycling stability subjectSolid-state batteries subjectVoltage hysteresis subjectconversion cathodes subject

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