Speakers

Solid polymer electrolytes (SPEs) are promising materials for promoting the safety of lithium batteries. One of the major challenges for developing SPEs is the synthesis process, which normally requires solvents that are used in SPE preparation with subsequent vacuum removal. This study employs liquid phase monomers and oligomers as the precursors for SPE synthesis. The prepared SPE contains sites of carbonyl C=O and amino N-H functionalities, which dissociate lithium salts by forming deep-eutectic-solvent-like domains in the polymer framework to facilitate ion transport. Polyethylene oxide-based polymer chains are crosslinked to contain carbonyl C=O and amino N-H functionalities in the polymer framework, which is incorporated with appropriate lithium salts to form Carbonyl-based SPE (CSPE). The CSPE has a high ionic conductivity and a high lithium-ion transference number at room temperature, and exhibits outstanding electrochemical stability of >5.5 V (vs. Li/Li⁺). Full cells Li|CSPE|LiFePO₄ and Li|CSPE|NMC₈₁₁ with low anode/cathode Li-ratios deliver charge-discharge cycling retentions of more than 95% of their initial capacities after 150 cycles, along with high average coulombic efficiencies. The CSPE is fire-retarding when exposed to a flame gun.