Zeolitic imidazolate framework upgrading polyethylene oxide composite electrolyte for high-energy solid-state lithium batteries.

The energy density of solid-state lithium batteries (SSLBs) has been primarily limited by the low ionic conductivity of solid electrolyte and poor interface compatibility between electrolyte and electrodes. Herein, a multifunctional composite solid polymer electrolyte (CSPE) based on polyethylene oxide (PEO) embedded with zeolitic imidazolate framework-8 deposited on carboxymethyl cellulose (ZIF@CMC) is reported. The ZIF@CMC interpenetrated in PEO matrix creates a continuous Li conductive network by combining Zn in ZIF with the unsaturated group in PEO to boost the Li transport through the PEO chain segment. On the other hand, Zn can bond with bis(trifluoromethane)sulfonimide (TFSI) anion, thus promoting the dissolution of lithium salt and releasing more lithium ions. This CSPE demonstrates brilliant electrochemical properties, including a high ionic conductivity of 1.8 × 10 S cm at room temperature and a wide electrochemical window of 5 V. The integrated LiFePO/CSPE/Li batteries using 20 wt.% ZIF-8@CMC show excellent reversible capacity of 145.6 mAh g with a capacity retention of 88.95 % after 200 cycles at a high current density of 0.5C. Our study proposed a novel and effective strategy to construct high-performance solid-state lithium batteries.