LiNi_1/3Co_1/3Mn_1/3O₂ hollow nano-micro hierarchical microspheres with enhanced performances as cathodes for lithium-ion batteries

LiNi_1/3Co_1/3Mn_1/3O₂ hollow nano-micro hierarchical microspheres (NCM-HS) are synthesized using MnCO ₃ both as a self-template and Mn source. The hollow microspheres with diameters of about 1 μm have walls about 250 nm thick, which are composed of approximately 100 nm primary nanoparticles. NCM-HS cathodes have an initial discharge capacity of 212 mA h g^-1 at 0.1 C between 2.5 and 4.5 V. After 40 charge-discharge cycles, the capacity retention at 0.1 C is 85.1%. At higher rates, the reversible capacities of the NCM-HS cathodes are 208.9 (0.5 C), 204.8 (1 C), 180.7 (2 C), 155.7 (5 C) and 135.9 mA h g^-1 (10 C). The high performances can be attributed to the distinctive hollow microspherical structures with the 100 nm building blocks, which could effectively reduce the path of Li ion diffusion, increase the contact area between electrodes and electrolyte and buffer the volume changes during the Li ion intercalation/ deintercalation processes.