Aquaporin-Inspired Chitosan/Cellulose Composite Membranes for Fuel Cells

The commercialization of proton-exchange-membrane fuel cells is constrained by the limitations of perfluorosulfonic acid membranes like Nafion, which suffer from high methanol crossover, humidity-dependent conductivity, high cost, and poor environmental sustainability. This review presents a comprehensive analysis of aquaporin-inspired chitosan/cellulose (AQP-CS) composite membranes as a transformative, bio-inspired alternative. The central design paradigm integrates a sustainable chitosan/cellulose matrix—which offers inherent mechanical stability, tunable proton conduction, and excellent fuel barrier properties—with biomimetic water channels engineered for selective hydration transport. This synergistic architecture aims to fundamentally decouple water management from proton conduction, directly addressing the core performance flaw of conventional membranes. The review is structured to explicitly trace the logical pathway from the foundational material properties of chitosan and cellulose to the functional requirements for integrating synthetic aquaporin-mimetic components. Experimental evidence from advanced chitosan composites, demonstrating proton conductivities up to 0.131 S cm−1 alongside drastically reduced methanol permeability, validates the potential of this approach. Consequently, AQP-CS composites establish a novel framework for developing next-generation fuel cell membranes that combine high performance with ecological design. However, key challenges in the stable integration of biomimetic channels, long-term operational durability, and scalable manufacturing must be resolved to enable practical deployment and mark a significant leap toward sustainable energy conversion technologies.