Post-treatment-induced structural reconstruction of hard carbon toward optimized sodium storage: A perspective and review

Hard carbon is considered as the preferred negative electrode material for the next generation of sodium-ion batteries (SIBs) due to its advantages of low potential, high capacity, high stability, and low cost. The preparation and modification of hard carbon are important steps in realizing its performance, and provide regular references for the study of sodium storage mechanisms. As a conventional modification method, post-processing is widely used for secondary processing of materials due to its flexibility. The advantage of post-processing is that it provides a more intuitive understanding of the impact on the structure, which is beneficial for determining the correlation between structural changes and performance discrepancy. This review provides a systematic summary and analysis of the post-treatment of hard carbon, including mechanical processing, thermal reconstruction, surface coating, doping modification. In addition, the relationship between carbon structure and electrochemical properties is unveiled. These insights offer profound prospects for the future development of hard carbon, which are expected to provide vital guidelines for developing next-generation high-performance SIBs.