LiNi_1/3Co_1/3Mn_1/3O₂ nanosheets were prepared via a facile co-precipitation and hydrothermal method. The structure and morphology evolution mechanism was disclosed through temperature and time-dependent experiments. Tested as materials of Li-ion batteries, LiNi_1/3Co_1/3Mn_1/3O₂ nanosheets presented attractive electrochemical performances. The capacities were over 193 mAh·g⁻¹ for initial charge, 189 mAh·g⁻¹ after 100 cycles at 0.2C, and 155 mAh·g⁻¹ after 400 cycles at 1C. The 1D nanosheets assembly interior endow this material efficient contact with electrolyte, short Li⁺ diffusion paths, and sufficient void spaces to accommodate large volume variation. The LiNi_1/3Co_1/3Mn_1/3O₂ with rationally designed nanostructures is a promising anode candidate for Li-ion batteries.