An impressive approach to solving the ongoing stability problems of LiCoPO 4 cathode: Nickel oxide surface modification with excellent core–shell principle

Abstract

Abstract Nanoscale and NiO-coated LiCoPO 4 cathode materials were prepared for the first time by a newly designed three-step synthesis route, which is a combined technique including advantages of the Stober, hydrothermal and microwave synthesis methods. Using this extraordinary technique, LiCoPO 4 particles are coated with a thin NiO layer with a perfect core-shell morphology and the technique's positive contribution to electrochemistry is elucidated in detail. The samples are interpreted using opto-analytical techniques and galvanostatic charge-discharge tests. The high-resolution transmission electron microscopy analysis proves that this well-elaborated technique makes it possible to achieve a continuous NiO surface coverage of 8–10 nm, a result that contributes towards solving the chronic electrochemical problems of 4.8 V cathode material. Our data reveal that NiO-coated LiCoPO 4 cathode demonstrates superior cycle stability and specific capacity at relatively low rates. The 2.5% wt. NiO-coated cathode exhibits the best electrochemical property, which reaches a discharge capacity of 159 mAh g −1 at 0.l C current rate and shows almost 85% capacity retention after 80 charge-discharge cycles. It therefore achieves partial success in improving the electrochemical properties of the LiCoPO 4 cathode material, which is especially crucial for energy storage to be applied in electric vehicles and plug-in hybrid electric applications.