A high-powered concentration-gradient Li(Ni0.85Co0.12Mn0.03)O2 cathode material for lithium ion batteries

• Concentration-gradient (Ni0.85Co0.12Mn0.03)(OH)2 is prepared via co-precipitation.
• Li(Ni0.85Co0.12Mn0.03)O2 contains 90% core material of Li(Ni0.9Co0.1)O2.
• Li(Ni0.85Co0.12Mn0.03)O2 has better electrochemical properties than Li(Ni0.9Co0.1)O2.
• The capacity of Li(Ni0.85Co0.12Mn0.03)O2 is 195 mAh g−1 at 1C between 2.8 and 4.3 V.
• The initial capacity retains 95.5% after 100 cycles.

A high-powered concentration-gradient cathode material with an average composition of Li(Ni0.85Co0.12Mn0.03)O2 has been successfully synthesized by a co-precipitation method. The Li(Ni0.85Co0.12Mn0.03)O2 has a core of Li(Ni0.9Co0.1)O2 that is rich in Ni and a concentration-gradient shell having decreased Ni content and increased Mn content. The electrochemical properties of the concentration-gradient material are studied and compared to those of the core Li(Ni0.9Co0.1)O2 material alone. In the concentration-gradient material of Li(Ni0.85Co0.12Mn0.03)O2, the Ni-rich core delivers a very high capacity, while the Mn-rich concentration-gradient shell improves the cycling stability and rate performance. The electrochemical properties of this cathode material are found to be far superior than those of the core Li(Ni0.9Co0.1)O2 material. At room temperature, the initial capacity of the concentration-gradient Li(Ni0.85Co0.12Mn0.03)O2 is 195 mAh g−1 at 1C between 2.8 and 4.3 V and retains 95.5% after 100 cycles. Moreover, the composite has a good rate performance with a high capacity of about 190 mAh g−1 even at 2C rate.