Carbon-Based Anode Materials for Metal-Ion Batteries: Current Status, Challenges, and Future Directions

The demand for effective, economical, and sustainable anode materials for metal-ion batteries (MIBs) has increased significantly due to the rapid growth of energy storage technologies. Among various candidates, carbon-based materials have emerged as highly promising due to their abundance, structural versatility, and favorable electrochemical properties. This review highlights the current status and future directions of carbon-based anode materials in MIBs, with a particular focus on graphite, hard carbon, carbon nanotubes, heteroatom-doped carbons, carbon-based composites, and other related structures. Various synthesis strategies for these materials are presented, along with discussions on their physicochemical characteristics, including structural features that influence electrochemical performance. Furthermore, we provided an overview on the performance of newly developed carbon-based anode materials in lithium-, sodium-, potassium-, and other emerging metal-ion battery systems to assess the impact of different synthesis approaches. Special attention is given to surface engineering, heteroatom doping, and composite design that can address intrinsic challenges such as limited ion diffusion, low reversible capacity, and poor cycling stability in MIBs. This review does not cover any carbon materials which have been used as an additive. In addition, the review explores emerging opportunities enabled by advanced characterization techniques, computational modeling, and artificial intelligence for optimizing the design of next-generation carbon anode. Finally, this article provides future perspectives and insights into the design principles of novel carbon-based anode materials that can accelerate the development of high-performance, durable, and sustainable MIB technologies.