Compatibility of Hard Carbon Anode in Li/Na-Ion Batteries: Precursor and Performance Insights

Hard carbon (HC) materials have emerged as promising anodes for sodium-ion batteries (SIBs) due to their low cost, disordered structure, and high reversible capacity. Moreover, several studies also prove that HC is compatible with lithium-ion batteries (LIBs), too. Although the demand for sustainable, low-cost, and high-performance energy storage systems is strong, HC is a potential anode material. This perspective includes a critical review of various precursors and their role in structural and electrochemical performances. Especially, coal precursors have been more emphasized in this review due to their widespread availability and contain naturally occurring doping elements (such as N and S). Furthermore, strategies for enhancing the performance, emerging trends, and future direction of research have also been critically reviewed, which have paved the pathways for high-performance and sustainable anode development for both LIBs and SIBs.