Recent Advances, Key Strategies, and Challenges in Fast-Charging Hard Carbon Anodes for Sodium-Ion Batteries

Abstract

Sodium-ion batteries (SIBs) have gradually entered the application market after years of development. To enhance user experience and reduce waiting time, the development of fast-charging SIBs has become an inevitable trend. However, hard carbon (HC) anode materials currently in use face significant challenges, such as capacity degradation and sodium metal plating during fast-charging. This paper explores the entire process of Na+ migration from the electrolyte to the bulk phase of the HC and examines the factors influencing Na+ migration at each stage. It then summarizes key strategies for achieving fast-charging HC for SIBs, with a focus on electrolyte optimization, surface coating, and bulk structural optimization. Finally, the paper highlights the main challenges and future prospects for developing fast-charging HC anodes, offering valuable insights for advancing fast-charging SIBs technologies.