Improved cyclic stability of LiNi0.8Mn0.1Co0.1O2 cathode enabled by a novel CEI forming additive
Zulipiya SHADIKE , Yiming CHEN , Lin LIU , Xinyin CAI , Shuiyun SHEN , Junliang ZHANG
Front. Energy ›› 2024, Vol. 18 ›› Issue (4) : 535 -544.
Improved cyclic stability of LiNi0.8Mn0.1Co0.1O2 cathode enabled by a novel CEI forming additive
The undesired side reactions at electrode/electrolyte interface as well as the irreversible phase evolution during electrochemical cycling significantly affect the cyclic performances of nickel-rich NMCs electrode materials. Electrolyte optimization is an effective approach to suppress such an adverse side reaction, thereby enhancing the electrochemical properties. Herein, a novel boron-based film forming additive, tris(2,2,2-trifluoroethyl) borate (TTFEB), has been introduced to regulate the interphasial chemistry of LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode to improve its long-term cyclability and rate properties. The results of multi-model diagnostic study reveal that formation lithium fluoride (LiF)-rich and boron (B) containing cathode electrolyte interphase (CEI) not only stabilizes cathode surface, but also prevents electrolyte decomposition. Moreover, homogenously distributed B containing species serves as a skeleton to form more uniform and denser CEI, reducing the interphasial resistance. Remarkably, the Li/NMC811 cell with the TTFEB additive delivers an exceptional cycling stability with a high-capacity retention of 72.8% after 350 electrochemical cycles at a 1 C current rate, which is significantly higher than that of the cell cycled in the conventional electrolyte (59.7%). These findings provide a feasible pathway for improving the electrochemical performance of Ni-rich NMCs cathode by regulating the interphasial chemistry.
NMC811 / cathode electrolyte interphase / film forming additives / cyclic stability
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Higher Education Press 2024
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