Regulating Li‐Ions Conduction of Eco‐Friendly Cellulose‐Based Composite Electrolytes via Amino‐Siloxane Functional Grafting for Sustainable Li‐Metal Batteries

ABSTRACT Cellulose‐based electrolytes are promising solid electrolyte candidates for low‐cost and eco‐friendly batteries owing to their natural characteristics of being renewable and biodegradable. Unfortunately, they have strong reactivity and high crystallinity, leading to critical challenges when used in Li‐ion batteries, including poor high‐voltage tolerance, slow Li‐ion conduction and heterogeneous Li‐ion flux. Here, we report a functional grafting modification to regulate Li‐ion conduction within cellulose‐based solid electrolytes. In‐situ sol‐gel self‐assembly accompanied by amino‐siloxane grafting is developed to achieve the homogeneous integration of cellulose−amino‐siloxane−ionic liquid composites, forming a compact solid‐state electrolyte membrane. Such functional design establishes continuous and uniform Li‐ion transport highways through amino coordination while disrupting native crystallinity of cellulose, endowing a rapid Li‐ion conductivity (1×10 −3 S cm −1 ) and a high electrochemical oxidation potential (5 V). The obtained electrolyte membrane features a homogenous microstructure with high mechanical elasticity and thermodynamic stability, exhibiting high compatibility with Li metal and enabling excellent electrochemical performance. Consequently, solid‐state Li‐metal batteries exhibit exceptional cycle‐life, whereas LiFePO 4 cells run 592 cycles and LiNi 0.8 Co 0.1 Mn 0.1 O 2 cells run 403 cycles at 0.5 C rate until the capacity reduces to 80%. Notably, a comprehensive life‐cycle assessment verifies its advantages in energy conservation and carbon reduction. It presents a sustainable development of high‐performance cellulose‐based solid‐state electrolytes.