Nonflammable all-fluorinated electrolytes enabling high-power and long-life LiNi0.5Mn1.5O4/Li4Ti5O12 lithium-ion batteries

Abstract

LiNi0.5Mn1.5O4 (LNMO)/Li4Ti5O12 (LTO) spinel-spinel batteries have appealing features of high energy, high power and inherent safety. However, cycling high-voltage LNMO cathodes causes severe oxidation of conventional carbonate-based electrolytes and leads to extensive capacity decay. Herein, we report that a nonflammable all-fluorinated electrolyte can support high-rate and inherent-safe 3.2 V LNMO/LTO batteries. The nanoscale fluorinated interphase stabilizes cathodic structure and suppresses side reactions during cycling, even at a high cutoff voltage of 5.0 V. The LNMO/Li cell in the all-fluorinated electrolyte delivers superior cyclability with 90.8 % capacity retention at 1 C over 1000 cycles. The LNMO/LTO cell exhibits great practical potential with capacity retention greater than 93.0 % over 1500 cycles at 5 C. In addition, the all-fluorinated electrolyte allows the LNMO/LTO cells to operate over wide temperatures. This work highlights a facile method for realizing the commercialization of LNMO/LTO lithium-ion batteries.