Low temperature combustion synthesis and performance of spherical 0.5Li2MnO3–LiNi0.5Mn0.5O2 cathode material for Li-ion batteries

The cathode material 0.5Li2MnO3–LiNi0.5Mn0.5O2 had been synthesized via low temperature combustion process followed by an annealing treatment. The microstructure and morphology characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) showed that the synthesized product had high crystallinity, α-NaFeO2-like layered structure, and sphere-like morphology. Its 0.1 C discharge capacity rapidly increased with cycle number before 6th cycle and reached the highest value 217 mAh/g at 14th cycle. After 50 cycles its 0.1, 0.2 and 0.5 C discharge capacities still retained 191.6, 187.8 and 156.2 mAh/g, respectively, showing that the synthesized product had excellent electrochemical performance.

The SEM image of the annealed product is shown in (a). The particle sizes are about 80–200 nm in diameter and aggregate together to form micro-spheres with many cavities, that should be beneficial to the penetration of the electrolyte. The micro-spheres are about 1–5 μm in diameter and well dispersed. (b) Shows that its discharge capacity is only 139 mAh/g at first cycle, but sharply increases to 193 mAh/g at 6th cycle and gradually increases to the highest capacity (217 mAh/g) at 14th cycle, and retains 191 mAh/g after 50 cycles. The difference from other cathode materials is that its discharge capacities do not decrease but rapidly increase in the first several cycles.Figure optionsDownload as PowerPoint slideHighlights
► Spherical cathode material had been successfully synthesized via low temperature combustion process.
► The cathode material had excellent electrochemical performance, and its discharge capacity was up to 217 mAh/g.
► The reason why the capacities do not decrease but rapidly increase in the first several cycles has been investigated.