A novel concentration-gradient Li[Ni0.83Co0.07Mn0.10]O2 cathode material was successfully synthesized viaco-precipitation, in which the core Li[Ni0.9Co0.05Mn0.05]O2 was encapsulated completely with a stable concentration-gradient layer having reduced Ni content. The electrochemical and thermal properties of the concentration-gradient Li[Ni0.83Co0.07Mn0.10]O2 were studied and compared to those of the core Li[Ni0.9Co0.05Mn0.05]O2 material alone. The concentration-gradient material had a superior lithium intercalation stability and thermal stability compared to the core material. The high capacity was delivered from the Ni-rich core Li[Ni0.9Co0.05Mn0.05]O2, and the improved thermal stability was achieved by the Ni-depleted concentration-gradient layer with outer surface composition of Li[Ni0.68Co0.12Mn0.20]O2. The concentration-gradient materials open a new era for the development of advanced Li-ion batteries with high energy density, long cycle life, and improved safety.