Research Review of Hard Carbon Anode Materials for Sodium-ion Batteries

Abstract

In recent years, sodium-ion batteries (SIBs) have been regarded as the most promising energy storage batteries to replace lithium batteries for their abundant resources and excellent energy storage capabilities. There are many kinds of anode materials for SIBs, and hard carbon (HC) is considered the most promising anode material for SIBs for its lower cost and high reversible specific capacity. However, the research on HC anode materials is still immature with some problems such as poor cycle performance, low initial Coulombic efficiency and difficult commercialization. In order for HC anode materials to meet the needs of SIBs, the principles of HC for optimization should be understood. This paper reviews recent research on the sodium storage mechanism of HC anode materials and design methods to optimize their electrochemical performance, and introduces four storage mechanisms of sodium ions and optimized modification methods of HC anode materials, which provide references for the research of advanced SIBs.