The high capacity of Ni-rich Li[Ni1-xMx]O-2 (M = Co, Mn) is very attractive, if the structural instability and thermal properties are improved. Li[Ni0.5Mn0.5]O-2 has good thermal and structural stabilities, but it has a low capacity and rate capability relative to the Ni-rich Li[Ni1-xMx]O-2. We synthesized a spherical coreshell structure with a high capacity (from the Li[Ni0.8Co0.1Mn0.1]O-2 core) and a good thermal stability (from the Li[Ni0.5Mn0.5]O-2 shell). This report is about the microscale spherical core-shell structure, that is, Li[Ni0.8Co0.1Mn0.1]O-2 as the core and a Li[Ni0.5Mn0.5]O-2 as the shell. A high capacity was delivered from the Li[Ni0.8Co0.1Mn0.1]O-2 core, and a high thermal stability was achieved by the Li[Ni(0.5)Nn(0.5)]O-2 shell. The core-shell structured Li[(Ni0.8Co0.1Mn0.1)(0.8)(Ni0.5Mn0.5)(0.2)]O-2/carbon cell had a superior cyclability and thermal stability relative to the Li[Ni0.8Co0.1Mn0.1]O-2 at the 1 C rate for 500 cycles. The core-shell structured Li[(Ni0.8Co0.1Mn0.1)(0.8)(Ni0.5Mn0.5)(0.2)]O-2 as a new positive electrode material is a significant breakthrough in the development of high-capacity lithium batteries.