Article

Electrolyte Salts for Sodium-Ion Batteries: NaPF<sub>6</sub> or NaClO<sub>4</sub>?

Fangyuan ChengState Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of ChinaMeilian CaoState Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of ChinaQing LiState Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of ChinaChun FangState Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of ChinaJiantao HanState Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of ChinaYunhui HuangState Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China

2023en

ABI

Abstract

NaClO4 and NaPF6, the most universally adopted electrolyte salts in commercial sodium-ion batteries (SIBs), have a decisive influence on the interfacial chemistry, which is closely related to electrochemical performance. The complicated and ambiguous interior mechanism of microscopic interfacial chemistry has prevented reaching a consensus regarding the most suitable sodium salt for high-performance SIB electrolytes. Herein, we reveal that the solvation structure induced by different sodium salt anions determines the Na+ desolvation kinetics and interfacial film evolution process. Specifically, the weak interaction between Na+ and PF6– promoted sodium desolvation and storage kinetics. The solvation structure involving PF6– induced the anion’s preferential decomposition, generating a thin, inorganic compound–rich cathode–electrolyte interphase that ensured interface stability and inhibited solvent decomposition, thereby guaranteeing electrode stability and promoting the charge transfer kinetics. This study provides clear evidence that NaPF6 is not only more compatible with industrial processes but also more conducive to battery performance. Commercial electrolyte design employing NaPF6 will undoubtedly promote the industrialization of SIBs.

Identifiers

DOI: 10.1021/acsnano.3c07474

Citations and references

Cited by 20 references

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