Electrochemical intercalation of Ca2+ ions into TiS2 in organic electrolytes at room temperature

Abstract

This work investigates the electrochemical intercalation of Ca2+ ions into TiS2 in organic electrolytes at room temperature and demonstrates that successful intercalation/de-intercalation can be achieved using a 0.1 M solution of Ca(CF3SO3)2 in propylene carbonate (PC) as an electrolyte. Additionally, further performance (charge/discharge capacity, reversibility, and hysteresis) enhancement is observed when a 0.1 M solution of Ca(CF3SO3)2 in a 1:10 (mol/mol) mixture of PC and dimethyl carbonate (DMC) is employed, which is ascribed to the modulation of the solvation environment of Ca2+ ions by the use of the relatively low-polar DMC. Finally, the structural changes in TiS2 caused by Ca2+ intercalation/de-intercalation during charge/discharge are probed by in situ X-ray diffraction analysis. Keywords: Calcium-ion batteries, TiS2 electrode, Organic electrolyte, In situ X-ray diffraction analysis