A Critical Review on Electrochemical Properties and Significance of Orthosilicate‐Based Cathode Materials for Rechargeable Li/Na/Mg Batteries and Hybrid Supercapacitors

The polyanion orthosilicates such as Li 2 XSiO 4 (X=Fe, Mn, Co, Ni), Na 2 XSiO 4 (X=Fe, Mn, Co, Ni) and MgXSiO 4 (X=Fe, Mn, Co, Ni) have been considered as viable cathode materials for the Li/Na/Mg batteries and hybrid supercapacitors. Significant capacity fading, structural instability, and low conductivity are the major impediments in silicate‐based cathode materials, which limit their practical applicability and industrial implementation. Identifying the source of capacity fading in these compounds upon cycling would offer better insight which merely reporting in previous efforts. The primary aim of this systematic review is to provide a clear insight on structure, morphology, electrical and electrochemical advances, and major impediments in the Li 2 XSiO 4 , Na 2 XSiO 4 and MgXSiO 4 type electrode materials. This study also compared the electrochemical results of various orthosilicate materials and discussed the mechanism of structural fracture during cycling. Among the numerous silicates, Li 2 FeSiO 4 and Li 2 MnSiO 4 are considered as promising cathode materials for advanced LIBs. This review also offers future opportunities and possible solutions to the structural and electrochemical inhibitions in Li 2 XSiO 4 , Na 2 XSiO 4 and MgXSiO 4 based‐electrodes for the development of rechargeable Li/Na/Mg batteries and hybrid supercapacitors.