A High-performance Lithium Metal Battery with a Multilayer Hybrid Electrolyte

Abstract

Solid-state batteries have been considered as a good choice for substituting traditional batteries with liquid electrolytes because of their high energy density and safe property. However, a little amount of flammable non-aqueous liquid electrolyte or polymer electrolyte is usually required to improve the interfacial contact, which is adverse to safety. Here, a nonflammable gel is prepared by hydrogen-bond interaction and applied as an interfacial layer to improve the performance of solid-state batteries. The prepared multilayer hybrid electrolyte (MHE) composed of gel and CPE shows a wide electrochemical window (5.3 V vs Li/Li+), high ionic transference number (0.57), and ionic conductivity (7.18 × 10−4 S cm−1) at room temperature. Thus, the assembled Li symmetric cell with MHE can cycle over 650 h at 0.5 mA cm−2 with a lower overpotential of ~61 mV. The LiFePO4|MHE|Li cell exhibits a higher discharge capacity of 107.8 mAh g−1 even cycled at 5 C. It also shows superior capacity retention of 96.4% after 1000 cycles at 0.5 C. This work provides a promising strategy for designing high-performance solid-state batteries.