Surface modification of cathode materials for energy storage devices: A review

With an advanced understanding of cathode materials in Li-ion batteries (LiBs) and supercapacitors, it has been observed that the surface structures of cathodes play an important role in these devices and significantly affects the whole system's performance e.g. maintain the structural stability and material's conductivity. Various approaches are being applied to enhance the electrochemical performances of batteries and supercapacitors e.g. doping of transition metal ions, synthesis of composite materials, synthesis of nanomaterials, and surface modification of materials. Among these techniques, surface modification of the electrode materials is widely used because of ease of synthesis and cost effectiveness. In the present article, the recent advancements in surface modifications of the energy storage electrode materials and their electrochemical performances are summarized. First, coating strategies and their effects on cathode are discussed and then the current research progress focusing on the surface coating materials are covered. At last, the challenges faced are discussed to improve the performances of cathode materials. In this study, we are presenting that the selection of coating materials and technologies plays a vital role in the advancement of cathode materials.