Bio-based materials for batteries and supercapacitors: Innovations in sustainable energy systems — A comprehensive review

Global transition toward renewable energy sources and decarbonization has increasing demand for advanced energy storage systems, particularly high-performance batteries and supercapacitors, capable of supporting intermittent renewables and electrified transportation. Conventional energy storage devices depend heavily on petroleum-derived materials, raising concerns over resource depletion, environmental impact, and long-term sustainability. Bio-based materials derived from renewable biomass feedstocks, such as lignocellulose, agricultural waste, algae, and natural polymers, offer a promising alternative due to their abundance, low cost, biodegradability, and reduced C-footprint. Review comprehensively examines recent progress in bio-based materials for energy storage applications, focusing on three major classes: 1) biomass-derived carbons (e.g., hard carbons for sodium-ion battery anodes achieving >400 mAh g −1 specific capacity and activated carbons for supercapacitors exceeding 300 F g −1 ), 2) natural polymers and gel electrolytes (e.g., cellulose- and chitosan-based systems with ionic conductivities >10 −3 S cm −1 ), and 3) bio-inspired composites/hybrids. Achievements include enhanced cycling stability (>5000 cycles in full cells), improved rate performance, and successful device-level integration in flexible and prototype systems. Sustainability assessments highlight favourable life-cycle impacts compared to synthetic counterparts. Despite these advances, challenges persist, including performance gaps relative to commercial benchmarks, variability in biomass precursors, scalability issues, and potential land-use conflicts. Future directions emphasize genetic engineering of feedstocks, multifunctional designs (e.g., self-healing), AI driven material optimization, and expansion to emerging battery chemistries. Aligning with circular economy principles and UN Sustainable Development Goals (SDGs, 7, 12, 13), bio-based materials hold transformative potential to enable truly green energy storage technologies by 2030–2040.