Paper – Self-purifying electrolyte enables high energy Li ion batteries.
Conventional LiPF6/carbonate electrolyte with poor oxidative stability and reactive decomposition products (HF, PF5, POF3, etc.) dictates less-stable electrode/electrolyte interphases, which thereby promotes the dissolution of transition metal ions, accelerates constant decomposition of electrolyte solvent, and results in the degradation of LIBs.
Herein, we demonstrate a new type of electrolyte, id est, 1.6 M lithium bis(fluorosulfonyl)imide (LiFSI) in (2-cyanoethyl) triethoxysilane (TEOSCN) with self-purifying feature.
TEOSCN molecules in electrolyte can effectively eliminate the reactive pernicious species, while the anions of FSI– dominate the interphase components with low-resistance on both graphite and Ni-rich NMC cathode although at an essentially low concentration.
This self-purifying electrolyte system enables long-term cycling of MCMB||NMC811 full-cells for 1000 cycles with an ultra-high capacity retention of 91% at 25 °C and for 500 cycles with a retention of 81% at 60 °C. Even in extreme cases, i.e., exposed in the air for 1 h, this electrolyte can still allow stable charge-discharge cycling of MCMB||NMC811 full-cells without degradation, which can largely simplify the manufacturing processes of LIBs.
The ‘self-purifying-plus-passivation’ strategy opens a promising frontier for the electrolyte engineering towards next-generation high-energy LIBs.
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Self-purifying electrolyte enables high energy Li ion batteries, May 16, 2022
