Cu3(OH)2V2O7·2H2O@rGO with bimetallic redox activity as a novel cathode material for calcium–ion batteries

• Published in: New journal of chemistry 2023-03, Vol.47 (17), p.8326-8333
• Main Authors: Tan, Xingnian, Wang, Junjun, Shuhan Jin, Wang, Yu, Fan Qiao, Zhang, Lei, An, Qinyou
• Format: Article
• Language: English
• Subjects: Bimetals; Calcium ions; Cathodes; Electrode materials; Electron microscopes; Graphene; Lithium-ion batteries; Photoelectrons; Room temperature
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj00886j

Owing to the abundance of calcium and low redox potential and high safety, calcium–ion batteries (CIBs) are considered a promising candidate for post lithium–ion batteries. However, the lack of high-performance cathode materials is one of the main obstacles to the development of CIBs. Herein, a monoclinic Cu3(OH)2V2O7·2H2O coated with reduced graphene oxide (CVO@rGO) is prepared using a facile one-step coprecipitation strategy without a surfactant at room temperature and proposed as a novel cathode material for CIBs. CVO@rGO shows a high discharge capacity of 189.9 mA h g−1, an excellent rate performance (55.4 mA h g−1@1000 mA g−1) and can be used for 1000 cycles with a capacity retention of 84.2%. In addition, the Ca2+ storage mechanism of CVO@rGO based on the conversion reaction is revealed using in situ X-ray diffraction and an ex situ transmission electron microscope, and the bimetallic redox activity of CVO@rGO is confirmed using the ex situ X-ray photoelectron spectra and a transmission electron microscope. This work provides a new direction for developing high-performance cathode materials with bimetallic redox activity for CIBs.