Facile synthesis and electrochemical properties of truncated octahedral Al, Ni dual doped LiMn2O4 cathode materials

Electrochemical properties of spinel LiMn2O4 still suffer from notorious Mn dissolution and Jahn-Teller distortion. Herein, a series of LiAl0.1NixMn1.90-xO4 (x = 0–0.10) cathode materials were prepared via a facile solid-state combustion combined with elements doping and morphology controlling strategy. All as-prepared samples possess a good spinel structure without any impurity. Rietveld refinements results illuminate that Al,Ni co-doping gives rise to the shrinkage of MnO6 octahedron and expansion of LiO4 tetrahedron, thereby improving the structural stability and restraining the Jahn-Teller distortion of the LiMn2O4. The Al,Ni co-doped spinel LiMn2O4 exhibits truncated octahedral particles with well-developed crystal facets of (111), (110) and (100), in which (111) facets suppress the Mn dissolution, while (110) and (100) facets boost Li+ ions diffusion. Consequently, the truncated octahedral LiAl0.1Ni0.03Mn1.87O4 sample delivers high discharge capacity and long cycled stability. At relatively high current rates of 10 C, 15 C and 20 C, the initial discharge capacities of 100.2, 96.1 and 92.9 mAh/g are achieved, the corresponding capacity retention ratios are 82.4%, 79.0% and 74.9% after 1000 cycles, respectively. This work will lay a certain foundation for the development of high-performance lithium-ion batteries in the future.