Dual Insurance Design Achieves Long-Life Cycling of Li-Metal Batteries under a Wide Temperature Range

Li-metal batteries show great potential in energy storage devices but still suffer a lot from dendrite growth, which restricts its long-time application due to safety and cycling concerns. Here, a dual insurance system is reported to avoid short-circuit occurrence and cycling performance decline through a two-step procedure. An Al2O3/PVDF-HFP layer is sandwiched into the in situ polymerized PMMA coat. The PMMA is so hard that the dendrites are not easy to impale; moreover, the electrospun Al2O3/PVDF-HFP layer could react with plunged lithium dendrites and inhibit the short circuit from occurring. Not only does the obtained composite polymer electrolyte (CPE) ensure desirable ionic conductivity (3.43 × 10–4 S cm–1 at 25 °C), wide electrochemical window, and considerable cycling stability but also dendrite inhibition and cycling stability are improved. The assembled full cell could cycle steadily under a wide temperature range and current density with desirable performance, when compared with abnormal cycling of liquid electrolyte under elevated temperatures. This work combines two methods to ensure the safety of Li-metal batteries, which enlightens a new thought for safe electrolyte design.