Coupling Graphite with Lithium Terephthalate Organic Electrode in Solid Polymer Electrolytes.

Abstract

Organic electroactive materials (OEMs) are featured with superior structural designability and ready accessibility from biomass or industrial plastics recycling, and they have emerged as important building blocks for future battery technology. Coupling OEMs with nonvolatile solid electrolytes offers the possibility for improving the technological sustainability and inherent safety of rechargeable batteries. This report delves into the representative carbonyl-based OEM, lithium terephthalate (Li₂C₈H₄O₄, LTPA), and prevailing graphite anode, and systematically investigates their fundamental properties with polyether-based electrolytes utilizing two sulfonimide anions (i.e., bis(fluorosulfonyl)imide and bis(trifluoromethanesulfonyl)imide), aiming to elucidate the unique features of OEMs and its synergy with salt anions. Results show that LTPA suffers from poor electronic conductivity in polymer electrolytes, while parasitic side reactions and cointercalation of low-molecular-weight compounds handicap neat graphite materials. Surprisingly, blended composite electrodes comprising graphite and a small portion of LTPA exhibit higher Coulombic efficiency and better capacity retention over continuous cycles, with significant improvement in the electrochemical utilization degree of graphite. The synergy between OEMs and classic graphite electrode materials in polymer electrolytes may spur the architectural design of solid-state batteries, and promote the realization of more sustainable battery technology in the near future.