Double‐Donor and Anion‐π Polymer Electrolytes for Fast Li + Conduction in Lithium Metal Batteries

Abstract Cellulose‐based quasi‐solid polymer electrolytes (QPE) offer advantages such as cost‐effectiveness, renewability, and environmental friendliness, making them ideal candidates for lithium metal batteries. However, the strong intermolecular hydrogen bonds within the cellulose framework hinder lithium ion (Li + ) transport and reduce ion mobility, limiting their practical applications. In this study, we developed a cellulose trimellitate ester (PCLA) with a double‐donor and anion‐π structure: 1) the carbonyl group (C═O) as a Li + donor, 2) the carboxyl group (COOH) serves as a hydrogen bond donor to anchor the bis(trifluoromethanesulfonyl)imide (TFSI − ) anion, and 3) the electron‐deficient benzene ring (Ph) interacts with the TFSI − anion through the anion‐π mechanism. The resulting PCLA QPE achieved high ionic conductivity (1 × 10 −3 S cm −1 at 25 °C) and excellent tensile strength (57.04 MPa). Full‐cell batteries with LFP and NCM811 cathodes exhibited exceptional cycling stability with remaining 85% and 90% of their initial capacity after 1000 and 200 cycles, respectively. This double‐donor and anion‐π molecular design paves the way for cellulose‐based solid electrolytes with commercial potential, advancing next‐generation safe energy storage technologies.