Physical and electrochemical properties of spherical Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}/MnO{sub 2} composite as a cathode for rechargeable lithium-ion battery

Graphical abstract: MnO{sub 2} was blended into pristine Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2} and Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}/MnO{sub 2} composite was obtained. We can observe that the adding MnO{sub 2} in the composite participates in the electrochemical reaction and provide more active sites for lithiation/delithiation. - Highlights: • Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}/MnO{sub 2} composite was synthesized by incorporation of MnO{sub 2} into spherical Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}. • Properties of spherical Li-rich layered oxide can be greatly improved by adding MnO{sub 2}. • The reason for the improvement of Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}/MnO{sub 2} by adding MnO{sub 2} was explained. - Abstract: Spherical Li-rich layered Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2} with high tap density and low specific surface area was synthesized. Furthermore, low cost and environmental benign MnO{sub 2} was blended into it and Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}/MnO{sub 2} composite was obtained. The properties of the materials were investigated by XRD, SEM and electrochemical method. The results showed that the existence of MnO{sub 2} in the composites can't change the structure of the pristine Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}. The electrochemical characteristics of Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}/MnO{sub 2} such as the initial coulombic efficiency, discharge capacity, rate characteristics and cyclability are much better than those of the pristine Li[Li{sub 0.2}Mn{sub 0.44}Ni{sub 0.18}Co{sub 0.18}]O{sub 2}. The contribution of MnO{sub 2} to the excellent characteristics of the cathode is as follows: the existence of MnO{sub 2} (i) provides more active site for lithiation/delitiation and (ii) suppresses side interaction between cathode particle surface and electrolyte.