Synthesis of Optimal NCA cathode using lithium zirconate coating to improve lithium-ion battery performance

In this study, the cathode material LiNi۰.۸Co۰.۱۵Al۰.۰۵O۲ was synthesized by continuous coprecipitation method and then calcined at different temperatures. The effect of calcination temperature on the structural and electrochemical properties of LiNi۰.۸Co۰.۱۵Al۰.۰۵O۲ was further evaluated. Structural studies were performed by X-ray diffraction pattern (XRD) and SEM images, and the electrochemical efficiency was performed by the application of galvanostatic charge / discharge cycles. The results of the study showed that calcination at ۸۰۰ C improves the properties and parameters of crystals and morphology of LiNi۰.۸Co۰.۱۵Al۰.۰۵O۲. Also, with calcination at this temperature, the initial charge-discharge capacity and cyclability have improved and the synthesized LiNi۰.۸Co۰.۱۵Al۰.۰۵O۲ electrical resistance has decreased, and as a result, its electrical conductivity has increased. In the second part, in order to increase the electrochemical performance, and cycling rates of LiNi۰.۸Co۰.۱۵Al۰.۰۵O۲ the coating were performed. The coating process is one of the common methods for improving the surface and electrochemical properties of cathode materials. Coating with lithium zirconate was performed by solgel process at different concentrations. Microstructural and electrochemical studies were performed on all samples. The results of the X-ray diffraction test showed that the cathode material with ۳% by weight of the coating had the best crystalline order and was free of any structural impurities. The SEM / EDS results showed that all samples had a smooth and uniform surface and that the coating elements were evenly distributed. The results of electrochemical tests showed that the sample with ۳% lithium zirconate coating had the best electrochemical properties in the field of first discharge-charge, rate capability and cycleability with ۱۸۴/۷ mAh / gr values of, reversible capacity of ۹۴.۷% ( after ۳۰ cycles in The C۲-C۰۵.۰ range ) and residual capacity is ۸۴.۴% (after ۸۰ cycles at ۰.۰۵ C) compared to other samples. The EIS measurement also indicated that it was more conductive than the NCA sample. It showed the effect of coating on improving structural and electrochemical properties compared to non-coating NCA sample.

کلیدواژه ها:

Lithium-ion batteries ، NCA cathode material ، coating ، lithium zirconate ، structural and electrochemical properties