Construction of LiMn(2)O(4) microcubes and spheres via the control of the (104) crystal planes of MnCO(3) for high rate Li-ions batteries

We have studied a synthetic route to control the morphology of MnCO(3) precursors. Taking the (104) crystal planes in the structure of MnCO(3) as the research point, the hydrothermal method was used to synthesize MnCO(3) cubes with highly exposed (104) crystal planes and densely crystallized MnCO(3) spheres by changing the water–ethanol reaction system. The MnCO(3) cubes and spheres were used as self templates to prepare spinel LiMn(2)O(4) by thermal decomposition and topological crystallization. The formation mechanism of MnCO(3) and LiMn(2)O(4) was analyzed using characterization methods such as X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. Electrochemical tests evidenced that the electrochemical performance of the as-made cubic and spherical LiMn(2)O(4) significantly improved compared with that of pristine LiMn(2)O(4). The results manifested that the LiMn(2)O(4) cubes and spheres have superior discharge capacity, delivering first discharge capacities of 130 and 115.1 mA h g(−1) at 0.5C, and 96.4 and 88.3 mA h g(−1) even at a high rate of 20C, respectively. After calculating the Li(+) diffusion coefficients of the samples, the results elicited that the diffusion ability of the Li(+) in the cubic and spherical LiMn(2)O(4) was significantly improved.