Synergetic effect of Ti-Mg-Sb tri-doping on enhanced electrochemical performance of LiCoO₂ at 4.6 V

With a theoretical specific capacity of 274 mAh·g⁻¹, LiCoO₂ (LCO) is the favored cathode material for lithium ion batteries (LIBs) applied to electronic devices. However, the unfavorable transitions in phase of LCO structure at high voltage and the negative reactions occurring at the interface between cathode and electrolyte limit the practical applications of LCO. Therefore, we designed a novel tri-doping strategy to enhance the electrochemical performance of LCO at 4.6 V. The introduction of minimal quantities of Ti, Mg, and Sb to the transition metal (TM) layer of LCO resulted in a substantial increase in both the cycling stability and reversible capacity of LCO. The distribution of the doping elements in the modified LCO was also analyzed, and we found that Ti, Sb were uniformly distributed in the particles, while Mg tended to distribute at the near-surface area of the primary particles. Through the trace Ti-Mg-Sb tri-doping, the modified LCO cathode material can reach an initial discharge capacity of 222.9 mAh·g⁻¹ between 3.0 and 4.6 V at 0.5 C with the capacity retention of 85.1% after 100 cycles. Moreover, the reversible capacity reached 114 mAh·g⁻¹ at 10 C. This research offers a promising future for the development of 4.6 V LCO, as well as valuable insight into designing subsequently multi-element co-doping schemes for LCO cathodes.