Cobalt-Doped Spinel Cathode for High-Power Lithium-Ion Batteries Toward Expanded Low-Temperature Applications

Lithium-ion batteries are widely used in electric vehicles and smart grids to facilitate fast and stable energy storage at different temperatures. However, the decreased Li+ diffusion and poor electronic conductivity of commercial cathode materials inevitably lead to irreversible energy degradation at low temperature. Herein, we tame the relationship between diffusion and temperature of spinel LiNi0.5Mn1.5O4 cathode by incorporating Co element into transition-metal sites. The Co element into the LiNi0.5Mn1.5O4 lattice effectively improves the diffusion properties of lithium ions, enhances its electronic conductivity, and prevents the dissolution of Mn. Therefore, LiNi0.4Co0.1Mn1.5O4 could deliver a capacity retention of 93.89% at 1 C after 200 cycles at 25 degrees C. Even at -20 degrees C, it delivers 88.43% of its room-temperature capacity. Moreover, the assembled LiNi0.4Co0.1Mn1.5O4/graphite and LiNi0.4Co0.1Mn1.5O4/Li4Ti5O12 full cells both show a capacity retention of 98.03 and 86.61% at 1 C after 100 cycles, respectively. In particular, the LiNi0.4Co0.1Mn1.5O4/ Li4Ti5O12 full battery still exhibits a discharge capacity of 116.9 mA h g-1 at -20 degrees C, reaching 90.24% of its room-temperature capacity. These results not only pave the way for improving the electrochemical performance of 5 V-based cathode materials but also provide insightful guidance for their commercial applications at low temperature.

Automated summary

By incorporating cobalt into the lattice of LiNi0.5Mn1.5O4 cathode, the diffusion properties of lithium ions are improved, electronic conductivity is enhanced, and dissolution of manganese is prevented, leading to improved performance of lithium-ion batteries at low temperatures. This research not only contributes to enhancing the electrochemical performance of 5 V-based cathode materials, but also provides useful guidance for their commercial applications at low temperature.