Mechanical Activation of Graphite for Na-Ion Battery Anodes: Unexpected Reversible Reaction on Solid Electrolyte Interphase via X-Ray Analysis

The research team led by Professor Seong Chan Jun of the Department of Mechanical Engineering (First author of this study are Su Chan Lee) and Dr. Chung KIST's team conducted a joint study under the theme of 'Mechanical Activation of Graphite for Na-Ion Battery Anodes: Unexpected Reversible Reaction on Solid Electrolyte Interphase via X-Ray Analysis'. In this paper, the sodium ion storage capacity of graphite was greatly improved through mechanical activation. The research team produced graphite with a defective structure using a ball milling technique, and analyzed its electrochemical performance using it as an SIB cathode. As a result, the activated graphite exhibited a sodium ion storage mechanism distinct from that of hard carbon. In the activated graphite, simultaneous reactions occurred at both the surface and bulk levels, with reversible reactions of Na2CO3 and NaF occurring on the SEI surface. This process enhanced the sodium storage performance by acting as an auxiliary sodium reservoir on the defect-rich carbon surface. The study demonstrated that the defect-rich carbon electrodes offer a new reaction mechanism characterized by unexpected reversible reactions on the SEI surface. This study was published in the world-renowned international journal 'Advanced Science' (Impact Factor: 15.1).

The link: https://doi.org/10.1002/advs.202401022