Evolving affinity between Coulombic reversibility and hysteretic phase transformations in nano-structured silicon-based lithium-ion batteries

• Published in: Nature communications Vol. 9; no. 1; pp. 479 - 17
• Main Authors: Ogata, K., Jeon, S., Ko, D.-S., Jung, I. S., Kim, J. H., Ito, K., Kubo, Y., Takei, K., Saito, S., Cho, Y.-H., Park, H., Jang, J., Kim, H.-G., Kim, J.-H., Kim, Y. S., Choi, W., Koh, M., Uosaki, K., Doo, S. G., Hwang, Y., Han, S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.02.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/131; 140/146; 639/301/299/161/891; 639/301/299/891; 639/4077/4079/891; 639/638/161/891; Anodes; Batteries; Commercialization; Electrochemistry; Electrode materials; Humanities and Social Sciences; Hysteresis; Lithium; Lithium-ion batteries; multidisciplinary; Phase transitions; Rechargeable batteries; Science; Science (multidisciplinary); Silicon
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-02824-w

Nano-structured silicon is an attractive alternative anode material to conventional graphite in lithium-ion batteries. However, the anode designs with higher silicon concentrations remain to be commercialized despite recent remarkable progress. One of the most critical issues is the fundamental understanding of the lithium–silicon Coulombic efficiency. Particularly, this is the key to resolve subtle yet accumulatively significant alterations of Coulombic efficiency by various paths of lithium–silicon processes over cycles. Here, we provide quantitative and qualitative insight into how the irreversible behaviors are altered by the processes under amorphous volume changes and hysteretic amorphous–crystalline phase transformations. Repeated latter transformations over cycles, typically featured as a degradation factor, can govern the reversibility behaviors, improving the irreversibility and eventually minimizing cumulative irreversible lithium consumption. This is clearly different from repeated amorphous volume changes with different lithiation depths. The mechanism behind the correlations is elucidated by electrochemical and structural probing. Using silicon electrodes could improve lithium ion battery storage capacities, but irreversible side reactions during cycling rapidly degrade current batteries. Here, the authors studied silicon-rich electrode phase transitions and how such transitions may benefit the rechargeable cell systems.