An Effectively Activated Hierarchical Nano-/Microspherical Li_1.2Ni_0.2Mn_0.6O₂ Cathode for Long-Life and High-Rate Lithium-Ion Batteries

Rechargeable lithium-ion batteries with high energy and high power density are required in the application of electric vehicles and portable electronics. Herein, we introduce a type of spherical Li-rich cathode material, Li_1.2Ni_0.2Mn_0.6O₂, assembled from uniform nanocubes by a facile polyvinylpyrrolidone (PVP)-assisted hydrothermal method. The material with a hierarchical nano-/microstructure exhibits stable high-rate performance. Furthermore, the precipitant (i.e., urea) and the structure-directing agent (i.e., PVP) effectively activated the Li₂MnO₃ components in the microscale material to achieve a high specific capacity of 298.5 mAh g^-1 in the first cycle. This Li-rich cathode material still delivered 243 mAh g^-1 at 0.1 C after 200 cycles and the capacity retentions at 0.5, 1, 2, and 5 C were 94.4, 78.7, 76.3, and 67.8 % after 150 cycles, respectively. The results make this Li-rich nano-/microstructure a promising cathode material for long-life and high-performance lithium-ion batteries.