Alginate Fiber Grafted Polyetheramine Driven High Ion Conductive and Flame-Retardant Solid Polymer Electrolyte for Lithium Metal Batteries

Abstract

Abstract Traditional poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) often suffer from inherent poor flame retardancy and unsatisfied ionic conductivity at room temperature, which seriously affect the safety and energy storage performance of lithium metal batteries (LMBs). Inspired by the mechanism of Li+ conductive in SPEs, an alginate fiber grafted polyetheramine (AF-PEA) membrane, capable of efficient Li+ transport and excellent flame retardancy is dedicatedly designed and synthesized as the backbone of SPEs for solid-state LMBs. Based on the intrinsic flame retardancy of the alginate fiber, the PEO casted AF-PEA (PEO@AF-PEA) shows self-extinguishing ability, and its Li+ transport ability is enhanced by grafting the ion conductive PEA chain segment. The LiFePO4/Li battery assembled using PEO@AF-PEA SPEs exhibits high safety and excellent cycling performance (exceeds 100 mAh g− 1 after 1500 cycles at 2 C current density and 80°C with less than 0.016% capacity decay of peer cycle). By simulating the transport and distribution of Li+ in the AF-PEA, the PEA with moderate chain lengths can uniformly fill the Li+ transport space between the alginate backbone to promote the Li+ adsorption and the utilization of Li+ anchoring points in PEA side chains, increasing the Li+ transport rate and migration capacity.