Dendrite-free Li Anode Enabled by a Metal–Organic Framework-Modified Solid Polymer Electrolyte for High-Performance Lithium Metal Batteries

Uncontrollable dendrite formation following the uneven deposition of lithium significantly affects the safety and service life of lithium metal batteries (LMBs). Therefore, a metal–organic framework solid polymer electrolyte (MSPE) with immobilized anions was prepared by the copolymerization of diallyl dicarbonate and a modified metal–organic framework material (MOFs). This not only avoids the agglomeration phenomenon caused by direct physical introduction of MOFs but also fixes the anion (TFSI–) by the numerous coordinated unsaturated cation sites exposed on the MSPE. Based on space charge theory, anion coordination is an effective lithium dendrite elimination method that results in protection of the lithium anode within LMBs. As a result, the assembled Li/LiFePO4 (LFP) cell exhibits a discharge specific capacity of 154.6 mA h g–1 and a capacity retention rate of 95.75% after 200 charge–discharge cycles at 0.2 C (1 C = 180 mA h g–1) at room temperature. More importantly, the assembled Li/Li symmetric cell with an MSPE exhibits a stable and low-potential cycle for 300 h at a current density of 0.5 mA cm–2 and achieves dendrite-free lithium deposition. This study provides a promising MOF-based solid polymer electrolyte for safe and high-performance LMBs.