Biochar‐Based Materials for Electrochemical Energy Storage

The global transition toward sustainable energy technologies is reshaping the design principles of electrochemical energy storage systems. Biochar, a tunable, carbon‐rich material derived from biomass, has emerged as a promising platform for next‐generation electrodes due to its abundant feedstock, cheapness, tailored porosity, intrinsic heteroatom content, and renewable origin. In this review, we critically examine recent advances in engineering the physicochemical properties of biochar to enhance its electrochemical performance in batteries. We highlight how microstructural control, surface functionality, and graphitization influence charge storage, ion diffusion, and cycling stability. Emphasis is placed on the interplay between synthesis conditions and electrochemical function, offering insights into structure–property relationships. Finally, we discuss the challenges of standardization, scale‐up, and environmental trade‐offs, and outline strategies for integrating biochar into scalable, low‐carbon energy storage technologies aligned with circular economy principles.