Physical and electrochemical properties of spherical Li[Li0.2Mn0.44Ni0.18Co0.18]O2/MnO2 composite as a cathode for rechargeable lithium-ion battery

Spherical Li-rich layered Li[Li0.2Mn0.44Ni0.18Co0.18]O2 with high tap density and low specific surface area was synthesized. Furthermore, low cost and environmental benign MnO2 was blended into it and Li[Li0.2Mn0.44Ni0.18Co0.18]O2/MnO2 composite was obtained. The properties of the materials were investigated by XRD, SEM and electrochemical method. The results showed that the existence of MnO2 in the composites canʹt change the structure of the pristine Li[Li0.2Mn0.44Ni0.18Co0.18]O2. The electrochemical characteristics of Li[Li0.2Mn0.44Ni0.18Co0.18]O2/MnO2 such as the initial coulombic efficiency, discharge capacity, rate characteristics and cyclability are much better than those of the pristine Li[Li0.2Mn0.44Ni0.18Co0.18]O2. The contribution of MnO2 to the excellent characteristics of the cathode is as follows: the existence of MnO2 (i) provides more active site for lithiation/delitiation and (ii) suppresses side interaction between cathode particle surface and electrolyte.