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Engineering Solid Electrolyte Interface at Nano‐Scale for High‐Performance Hard Carbon in Sodium‐Ion Batteries
Author(s) -
Ma Mengying,
Cai Haoran,
Xu Chenlu,
Huang Renzhi,
Wang Shurong,
Pan Huilin,
Hu YongSheng
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202100278
Subject(s) - electrolyte , materials science , electrochemistry , electrode , chemical engineering , layer (electronics) , carbon fibers , nanotechnology , ion , chemistry , composite material , organic chemistry , composite number , engineering
Engineering the structure and chemistry of solid electrolyte interface (SEI) on electrode materials is crucial for rechargeable batteries. Using hard carbon (HC) as a platform material, a correlation between Na + storage performance, and the properties of SEI is comprehensively explored. It is found that a “good” SEI layer on HC may not be directly associated with certain kinds of SEI components, such as NaF and Na 2 O. Whereas, arranging nano SEI components with refined structures constructs the foundation of “good” SEI that enables fast Na + storage and interface stability of HC in Na‐ion batteries. A layer‐by‐layer SEI on HC with inorganic‐rich inner layer and tolerant organic‐rich outer flexible layer can facilitate excellent rate and cycling life. Besides, SEI layer as the gate for Na + from electrolyte to HC electrode can modulate interfacial crystallographic structures of HC with pillar‐solvent that function as “pseudo‐SEI” for fast and stable Na + storage in optimal 1 m NaPF 6 ‐TEGDME electrolytes. Such a layer‐by‐layer SEI combined with a “pseudo‐SEI” layer for HC enables an outstanding rate of 192 mAh g −1 at 2 C and stable cycling over 1100 cycles at 0.5 C. This study provides valuable guidance to improve the electrochemical performance of electrode materials through regulation of SEI in optimal electrolytes.