Enhancing the Ion Transport Capacity of Composite Polymer Electrolyte via Covalent-Linked Two-Dimensional Layered MBene Nanomaterial for High-Performance Solid-State Lithium Metal Batteries

Improving the room temperature ionic conductivity of solid-state polymer electrolytes for lithium batteries is a big challenge. Exploring new composite polymer electrolytes is one of the important solutions. Herein, a new inorganic two-dimensional layered metal boride nanomaterial (MBene) was first applied to the polymer electrolyte. The hyperbranched cross-linking composite polymer electrolyte is prepared by free radical polymerization of double bond modified MBene and hyperbranched ether with double bonds in the presence of PVDF-HFP and lithium salt. c provided by the two-dimensional layered material and the characteristics of adsorbing lithium salt anion. As a result, the room temperature ionic conductivity of DBMBene-DBHPG-PH CPEs reaches 9.35 × 10^-4 S cm^-1. Combination of ATR-FTIR spectra, XANES spectra, and DFT calculation reveals the influence of MBene on ion transport. Dendrite-free growth with high reversibility can be maintained for more than 2000 h by lithium plating/stripping in lithium symmetric batteries. The solid electrolyte can be adapted to LFP and LMFP, NCM523 high-voltage cathode materials. It is worth mentioning that the assembled pouch cell also can run stably for 150 cycles at 0.1 C, showing higher cycle capacity. This work not only demonstrates a novel MBene-based composite polymer electrolyte and provides an effective strategy to prevent the aggregation of inorganic fillers in polymer electrolyte but also exhibits excellent application prospects of two-dimensional layered MBene material in solid polymer electrolyte for high-energy density solid-state lithium batteries.