Synthesis and Characterization of Li(Ni0.8Co0.1Mn0.1)0.8(Ni0.5Mn0.5)0.2O2 with the Microscale Core−Shell Structure as the Positive Electrode Material for Lithium Batteries

The high capacity of Ni-rich LiNi(1-x)M(x)O(2) (M = Co, Mn) is very attractive, if the structural instability and thermal properties are improved. LiNi(0.5)Mn(0.5)O(2) has good thermal and structural stabilities, but it has a low capacity and rate capability relative to the Ni-rich LiNi(1-x)M(x)O(2). We synthesized a spherical core-shell structure with a high capacity (from the LiNi(0.8)Co(0.1)Mn(0.1)O(2) core) and a good thermal stability (from the LiNi(0.5)Mn(0.5)O(2) shell). This report is about the microscale spherical core-shell structure, that is, LiNi(0.8)Co(0.1)Mn(0.1)O(2) as the core and a LiNi(0.5)Mn(0.5)O(2) as the shell. A high capacity was delivered from the LiNi(0.8)Co(0.1)Mn(0.1)O(2) core, and a high thermal stability was achieved by the LiNi(0.5)Mn(0.5)O(2) shell. The core-shell structured Li(Ni(0.8)Co(0.1)Mn(0.1))(0.8)(Ni(0.5)Mn(0.5))(0.2)O(2)/carbon cell had a superior cyclability and thermal stability relative to the LiNi(0.8)Co(0.1)Mn(0.1)O(2) at the 1 C rate for 500 cycles. The core-shell structured Li(Ni(0.8)Co(0.1)Mn(0.1))(0.8)(Ni(0.5)Mn(0.5))(0.2)O(2) as a new positive electrode material is a significant breakthrough in the development of high-capacity lithium batteries.