Ion‐Conducting Molecular‐Grafted Sustainable Cellulose Quasi‐Solid Composite Electrolyte for High Stability Solid‐State Lithium‐Metal Batteries

Abstract Cellulose‐based solid electrolyte possesses the characteristics of low cost, high strength, and sustainability, and has great potential in the field of solid‐state lithium metal batteries. However, the large hydrogen bonds between cellulose molecules make the molecular chains tightly arranged, and hinder the ion conduction, seriously limiting its further development. Herein, an ion‐conducting molecular grafting strategy is proposed for the fabrication of cellulose acetate quasi‐solid composite electrolyte (CLA‐CN‐LATP QCE) with a superior ionic conductivity of 1.25 × 10 ⁻³ S cm ⁻¹ at room temperature. Benefited from grafted functional molecules, the assembled symmetrical battery exhibits low polarization voltage and highly stable lithium stripping/plating cycling of more than 1200 h at 0.1 mA cm ⁻² current density. Moreover, it endows LFP|CLA‐CN‐LATP QCE|Li battery with excellent long‐cycle stability of 1500 cycles at 0.5 C and 25 °C and superior capacity retention of 92.1%. Importantly, this work provides an effective strategy for further opening the ion transport channel between cellulose molecular chains and improving the interface properties of electrolytes and electrodes.