Interfacial Modification of High‐Voltage LiCoO2 Materials via Ti/Mg Doping Strategy for Inhibiting Harmful Phase Transition Effect

ABSTRACT Developing high voltage lithium cobalt oxide (LiCoO 2 , LCO) is crucial for attaining the enhanced capacity and energy density of lithium‐ion batteries. However, severe interface and structural instability lead to rapid degradation of LCO under the condition of high voltage. Herein, a successful strategy for modifying the interface of LCO is developed using a one‐step high temperature process. By coating LCO with Li 3 TiMg(PO 4 ) 3 (LTMP), the obtained phosphate can stabilize the surface crystal structure and boost the mechanical stability of LCO. The high temperature process enables the successful doping of Ti/Mg into the LCO lattice, effectively inhibiting the harmful phase transition effect across various voltage ranges. Compared to commercial LCO and the reported studies, the modified LCO@LTMP performs outstanding electrochemical performance. It delivers an initial discharge specific capacity of 216.4 mAh·g −1 at 0.1 C and 189.98 mAh·g −1 at 1 C. After 250 cycles at 1 C, it preserves 87.46% of its initial capacity, manifesting excellent cycling stability. Moreover, it provides a discharge specific capacity of 115.9 mAh·g −1 at 5 C, demonstrating outstanding rate performance. This work holds great potential for practical applications and offers valuable guidance for developing other high performance cathode materials in rechargeable batteries.