Unraveling the Hydrolysis Mechanism of LiPF6 in Electrolyte of Lithium Ion Batteries.
Nano Lett
; 24(2): 533-540, 2024 Jan 17.
Article
em En
| MEDLINE
| ID: mdl-37982685
ABSTRACT
Lithium hexafluorophosphate (LiPF6) has been the dominant conducting salt in lithium-ion battery (LIB) electrolytes for decades; however, it is extremely unstable in even trace water (ppm level). Interestingly, in pure water, PF6- does not undergo hydrolysis. Hereby, we present a fresh understanding of the mechanism involved in PF6- hydrolysis through theoretical and experimental explorations. In water, PF6- is found to be solvated by water, and this solvation greatly improved its hydrolytic stability; while in the electrolyte, it is forced to "float" due to the dissociation of its counterbalance ions. Its hydrolytic susceptibility arises from insufficient solvation-induced charge accumulation and high activity in electrophilic reactions with acidic species. Tuning the solvation environment, even by counterintuitively adding more water, could suppress PF6- hydrolysis. The undesired solvation of PF6- anions was attributed to the perennial LIB electrolyte system, and our findings are expected to inspire new thoughts regarding its design.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Nano Lett
Ano de publicação:
2024
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Article