Defective Carbon for Next-Generation Stationary Energy Storage Systems: Sodium-Ion and Vanadium Flow Batteries

This review examines the role of defective carbon-based electrodes in sodium-ion and vanadium flow batteries. Methods for introducing defects into carbon structures are explored and their effectiveness in improving electrode performance is demonstrated. In sodium-based systems, research focuses primarily on various precursor materials and heteroatom doping to optimise hard carbon electrodes. Defect engineering increases interlayer spacing, porosity, and changes the surface chemistry, which improves sodium intercalation and reversible capacities. Heteroatom functionalisation and surface modification affect solid electrolyte interface formation and coulombic efficiencies. For flow batteries, post-fabrication electrode enhancement methods produce defects to improve electrode kinetics, although these methods often introduce oxygen functional groups as well, making isolation of defect effects difficult. Continued research efforts are key to developing carbon-based electrodes that can meet the unique challenges of future battery systems. Sodium-ion and vanadium flow batteries: Understanding the impact of defects in carbon-based materials is a critical step for the widespread application of sodium-ion and vanadium flow batteries as high-performance and cost-effective energy storage systems. In this review, various techniques for achieving such defect structural properties are presented, followed by an outline of their impact on the respective storage system.image