Electrophoretic deposition of graphene oxide as a stabilizing layer on the Ni-rich layered oxide electrodes for enhancing the cycling stability of Li-ion cathodes

Abstract

One of the critical challenges for layered Ni-rich cathode material is the surface degradation caused by the parasitic reaction between the cathode material and the organic electrolytes. Herein, we develop an overall electrode modification strategy to improve the cathode surface's structural stability by integrating graphene oxide (GO) coating on the surface of the cathode electrode with the assistance of the electrophoretic deposition technique (EPD). The attenuated total reflectance (ATR) and scanning electron microscope (SEM) results confirm the formation of the uniform thin GO layer on the surface of the Ni-rich cathode. The electrochemical studies such as galvanostatic charge-discharge, galvanostatic intermittent titration Technique (GITT), and incremental capacity analysis (ICA) tests show that the existence of thin layers of GO not only does not hinder the intercalation of Li+ ions but also can facilitate the charge transfer and intercalation of Li+ ions by decreasing the charge transfer resistance of the electrode. The cycling stability of the cathode coated with GO in 30 s of EPD shows better performance over 150 charge-discharge cycles and lower Rct than the pristine electrode. Our work provides a design idea for stabilizing the surface/bulk structure of advanced Ni-rich cathode for high-performance Li-ion batteries.