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

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.