Elucidating the Beneficial Effect of Vinylene Carbonate on the Electrochemistry of Antimony Electrodes in Lithium Batteries

Vinylene carbonate (VC) is an effective electrolyte additive for improving electrode performance in lithium‐ion batteries. We confirm its beneficial effects in a nanosized Sb–cellulose fiber composite electrode and examine its mechanism of action by X‐ray photoelectron spectroscopy, the most suitable technique for characterizing active particle surfaces (especially electrode/electrolyte interfaces). Vinylene carbonate clearly increases electrolyte stability (particularly that of LiPF₆) by avoiding the formation of a thick layer of LiF that conceals Sb and prevents its reaction with Li. Decreasing the layer thickness therefore increases the reversibility of the electrochemical reaction and improves capacity retention on cycling. The presence of VC afforded high‐quality Sb 4d and Li 1s photoemissions, fitting of which clearly exposed a previously unreported low‐energy component. We believe that this component is an Li_xSb alloy, which for the first time is identified spectroscopically.