Reconstruction and Deconstruction Strategies of Lignocellulose Biomass Toward Hard Carbon Anodes in Rechargeable Sodium Batteries: A Review

Sodium-ion batteries have emerged as promising alternatives to lithium-ion batteries due to their advantages of abundant resources, low cost, and environmental friendliness, which address the growing requirements for low energy storage cost and better environmental compatibility in large-scale energy storage. Hard carbon stands out as a promising anode material for sodium-ion batteries. Among various precursors for hard carbons, lignocellulose has been widely used as a natural and renewable precursor to prepare hard carbon anodes for its abundance of precursor, high carbon yields, and decent performance of the resultant hard carbons. Herein, this review provides a comprehensive overview of the research progress in lignocellulose-derived hard carbon anode materials. It first summarizes the sodium-ion storage mechanisms, characterization techniques for hard carbons and then revisits the pretreatment methods for lignocellulose, carbonization processes, and microstructure modulation methods for constructing hard carbons. Additionally, this review analyzes the existing challenges and technical bottlenecks hindering the practical application of lignocellulose-derived hard carbons. It also proposes future research directions, aiming to provide theoretical foundations and technical references for developing high-performance, low-cost, and sustainable hard carbon materials for sodium-ion batteries.