Reinforced Chitosan Polymer Electrolyte for Long‐Life and Robust Laminated Li‐Zn Structural Batteries

Abstract Aqueous zinc (Zn)‐based structural batteries, combining electrochemical energy storage with mechanical load‐bearing capabilities, are promising for next‐generation electric vehicle energy storage due to their eco‐friendly and safe nature. However, challenges such as dendrite formation, anode corrosion, and parasitic reactions limits practical application. Polymer electrolytes, particularly hydrogels, can mitigate these limitations, but typically possess poor mechanical properties that jeopardizes structural robustness. This article presents cellulose nanofibrils (CNF) reinforced chitosan as a novel polymer electrolyte system for aqueous Zn‐based structural batteries. Chitosan matrix, a hydratable plastic with superior mechanical properties to hydrogels, can manipulate solvation sheath of Zn²⁺ ions to enhance battery performance. When combined with CNF for reinforcement, ChitosanCNF electrolyte forms a robust, multifunctional material. A chitosan‐based glue improves the interface between electrodes and electrolyte in Zn||ChitosanCNF‐4||LiMn₂O₄(LMO)‐Carbon Fiber (CF) laminated battery, displaying excellent electrochemical performance with over 4500 h of cycling stability and 90% capacity retention. The lamination process also strengthens the battery, achieving an impressive tensile modulus of ≈8.48 GPa. The Zn||ChitosanCNF‐4||LMO‐CF battery is highly deformation‐resistant, abuse‐tolerant, and exhibits minimal self‐discharge, making it adaptable to complex configurations without additional support. Its structural integrity and space efficiency allow for seamless integration into infrastructure, a promising solution for low‐cost, sustainable, and high‐performance energy storage.