Lignin-enabled Li-ion battery components: recent advances and outlook

Abstract

With the finite nature of fossil resources, rising energy demands, and the environmental impact of conventional battery materials, the shift toward bio-based materials in energy storage systems has become crucial. Lignin, the second most abundant polymer in nature and a by-product of paper & pulping and ethanol production facilities, has attracted significant research interest due to its inherent benefits, including high carbon content, renewability, robust structure, and low cost. This critical review provides a comprehensive and comparative analysis of recent advances in the incorporation of lignin into lithium-ion battery components, including anodes, cathodes, binders, separators, and electrolytes. Beyond summarizing reported electrochemical performance, this review critically examines how lignin source, structural heterogeneity, molecular weight distribution, functional group chemistry, and fractionation strategies govern structure–property–performance relationships across different battery components. Lignin-derived hard carbons have demonstrated competitive anode capacities, reaching up to 602 mAh g⁻¹ in silicon–lignin composites, while lignin-based cathode systems exploit quinone-type redox activity in hybrid architectures. In non-active components, lignin-based binders and separators offer clear advantages through aqueous processability, strong adhesion, enhanced thermal stability, and improved electrolyte affinity, whereas lignin-containing polymer and gel electrolytes exhibit ionic conductivities up to 10⁻³ S cm⁻¹ at room temperature. Sustainability considerations, including life-cycle assessment, solvent replacement, recycling compatibility, and emerging commercialization efforts, are critically evaluated to contextualize lignin's realistic industrial potential. Despite these advances, challenges related to intrinsic conductivity, structural variability, interfacial stability, and long-term cycling still remain unsolved. This review identifies key research directions, such as controlled fractionation, targeted functionalization, and hybrid material design, required to bridge performance gaps and enable scalable, low-carbon lithium-ion battery technologies. To achieve commercialization, the lignin-derived batteries should have 1000 stable cycles, and over 250 Wh kg⁻¹ energy density, and cost less than $100 k⁻¹ Wh⁻¹.