Multistage bridge engineering for electrolyte and interface enables quasi-solid batteries to operate at -40°C

The practical application of solid-state batteries (SSBs) has been significantly hampered by the sluggish Li+ transport dynamics in cold climates. In particular, SSBs suffer from insufficient dynamics due to poor electrolyte-electrode interface compatibility at low temperatures. Herein, a multistage bridge engineering for electrolyte and interface is proposed to improve the Li+ transfer kinetics, which enables quasi-solid batteries to operate at low temperatures. The incorporation of siloxane segments allows the electrolyte to polymerise uniformly and improves Li+ transport. The multistage bridging structure improves the electrode-electrolyte interfacial interaction, accelerating Li+ transfer kinetics at low temperatures. The obtained Li||LiNi0.8Co0.1Mn0.1O2 (NCM811) cell delivers a high coulombic efficiency of 99.98 % and a specific energy of 266 Wh⋅kg−1 at -40 °C. This multistage bridge engineering strategy provides a new perspective for polymer electrolyte design towards stable operation of quasi-solid batteries at low temperatures.