High-safety polyurethane solid polymer electrolyte regulated by oxygen-enriched interface of nano-hydroxyapatite microspheres

Ameliorating the electrochemical performance and conquering its flammability are the crux to promoting the practical application of polyurethane solid polymer electrolytes (SPE) for safety lithium batteries. Herein, a novel non-flammable electrolyte membrane was developed by exploiting intrinsic flame retardant polyurethane as the skeleton and utilizing the oxygen-enriched interface of nano-hydroxyapatite (HAP) to regulate its ion transport performance. The FR-PU@HAP-Li electrolyte evinces benign self-extinguishing performance as well as exceptional heat suppression competence. Meanwhile, the oxygen-enriched interface of HAP increases the dissociation degree of lithium bis-(trifluoromethanesulfonyl)imide (LiTFSI) by providing an integrated dissociation-diffusion platform. Moreover, LiFePO4/FR-PU@HAP-Li/Li cell possesses an enhanced safety performance when encountering thermal runaway and long-term cycle stability with only 0.046 % average capacity attenuation per cycle within 200 cycles. Therefore, FR-PU@HAP-Li is supposed to propose a new strategy of surmounting the inherent defects of solid polymer electrolyte.