High rate performance and kinetic investigation of polyhedral Li1·05Mn1.95-xNixO4 cathode material

Abstract A series of Li1·05Mn1.95-xNixO4 (0≤ x ≤ 0.08) cathode materials were rapidly prepared by a facile solution combustion method. The effects of Ni-doping on the crystalline structure, morphology and electrochemical property were investigated detailedly. All the as-obtained samples show polyhedral morphology with a size distribution of 100–220 nm and correspond to the cubic spinel structure with high crystallinity. This unique polyhedron has abundant {111} facets that are aligned to the crystal orientations with a minimal Mn dissolution and exposes a small part of {110} and {100} facets that boost lithium ions diffusion. Benefiting from the appropriate Ni-doping and polyhedral morphology, which endow the Li1·05Mn1.95-xNixO4 with good rate capability and electrochemical cycling performance. Especially, the Li1·05Mn1·92Ni0·03O4 delivers the initial discharge capacity of 111.8 mA h/g at 5 C and retains the corresponding capacity retention of 72.4% after 1000 cycles at a high current rate of 10 C. Even under high temperature of 55 °C at 1 C, an initial high discharge capacity of 120.2 mA h/g and capacity retention of 65.8% are also obtained after 200 cycles. The polyhedral spinel Li1·05Mn1.95-xNixO4 cathode materials synthesized via the facile approach hold a great potential in the practical applications.