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

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 LiFePO₄ cells run 592 cycles and LiNi_0.8Co_0.1Mn_0.1O₂ 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.