This study explores the potential of titanium disulfide (TiS
2) as an active material for aqueous calcium-ion batteries (CIBs). We investigate the electrochemical redox reactions of calcium ions within TiS
2 and assess its suitability for use in aqueous CIBs. Additionally, we
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This study explores the potential of titanium disulfide (TiS
2) as an active material for aqueous calcium-ion batteries (CIBs). We investigate the electrochemical redox reactions of calcium ions within TiS
2 and assess its suitability for use in aqueous CIBs. Additionally, we examine the impact of varying electrolyte concentrations, ranging from 1.0 to 8.0 mol dm
−3, on TiS
2 electrode reactions. Our findings reveal that TiS
2 exhibits distinct charge–discharge behaviors in various aqueous calcium-ion electrolytes. Notably, at higher electrolyte concentrations, TiS
2 effectively suppresses the hydrogen generation reaction caused by water decomposition. In situ X-ray diffraction analysis confirms the intercalation of Ca
2+ ions between the TiS
2 layers during charging, which is a groundbreaking discovery, signifying TiS
2’s applicability in aqueous CIBs. X-ray photoelectron spectroscopy analysis further supports the formation of a solid electrolyte interphase (SEI) on the TiS
2 electrode surface, contributing to the suppression of electrolyte decomposition reactions. Furthermore, we investigate the influence of anions in the electrolyte on charge–discharge behavior. Our findings suggest that the choice of anion coordinated with Ca
2+ ions affects the SEI formation and cycling performance. Understanding the role of anions in SEI formation is crucial for optimizing aqueous CIBs. In conclusion, this research underscores TiS
2’s potential as an active material for aqueous calcium-ion batteries and emphasizes the importance of the electrolyte composition in influencing SEI formation and battery performance, contributing to sustainable and efficient energy storage technologies.
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