An effective dysprosium modification to enhance the structural stability and diffusion kinetics of LiCoO2 at high-voltage

As the most attractive cathode for digital devices, LiCoO2 can acquire a more specific capacity by raising the cut-off voltage. However, the unstable layered structure is considered a critical obstacle to the practical application of LiCoO2 at high-voltage. Herein, the dysprosium modification strategy to reinforce the structural stability of LiCoO2 at 4.5 V by the sloid-state method is proposed. Dysprosium doping enhances the stability of the Co-O chemical bonds, thus suppressing the lattice oxygen release during cycling at high-voltage. Meanwhile, the doping of dysprosium enlarges the c-axis spacing and restrains the formation of the Li-insulator Co3O4 phase, further providing a stable and expanded channel for the rapid intercalation/extraction of Li+. The dysprosium-modified LiCoO2 cathode material exhibits a discharge capacity of 162.1 mAh·g−1 with a retention rate of 81.1% after 400 cycles over 3.0–4.5 V at 1 C. Despite a higher current density of 8 C, the modified sample displays a discharge capacity of 154.4 mAh·g−1, with a retention rate of 93.3% after 300 cycles. Hence, it is believed that the study can provide some insights into enhancing the structural stability of cathode materials under high-voltage.