Dendrite-Free, Wide Temperature Range Lithium Metal Batteries Enabled by Hybrid Network Ionic Liquids

Ionic liquid N-methyl-N-propyl-pyrrolidinium bis(fluorosulfonyl)imide (PyrFSI) was introduced into a hybrid network to obtain a series of gel polymer electrolytes (GPEs). Mechanical and electrochemical properties of the GPEs were tuned through controlling the network structure and ionic liquid contents, and ionic conductivity higher than 1 mS cmat room temperature was achieved. The newly developed GPEs are flame-retardant and show excellent thermal and electrochemical stability as well as ultra-stability with lithium metal anode. Symmetrical lithium cells with the GPEs exhibit a stable cycling over 6800 h at a current density of 0.1 mA cmand stable lithium stripping-plating at 1 mA cm, the highest current density reported for ionic liquid-based GPEs. Moreover, Li/LiFePObatteries with the obtained GPEs exhibit desirable cycling stability and rate performance over a wide temperature range from 0° C. to 90° C.