Enhanced Electrochemical Performance of Li1.27Cr0.2Mn0.53O2 Layered Cathode Materials via a Nanomilling-Assisted Solid-state Process

Li1.27Cr0.2Mn0.53O2layered cathodic materials were prepared by a nanomilling-assisted solid-state process. Whole-pattern refinement of X-ray diffraction (XRD) data revealed that the samples are solid solutions with layered α-NaFeO2structure. SEM observation of the prepared powder displayed a mesoporous nature composed of tiny primary particles in nanoscale. X-ray photoelectron spectroscopy (XPS) studies on the cycled electrodes confirmed that triple-electron-process of the Cr3+/Cr6+redox pair, not the two-electron-process of Mn redox pair, dominants the electrochemical process within the cathode material. Capacity test for the sample revealed an initial discharge capacity of 195.2 mAh·g−1at 0.1 C, with capacity retention of 95.1% after 100 cycles. EIS investigation suggested that the high Li ion diffusion coefficient (3.89 × 10−10·cm2·s−1), caused by the mesoporous nature of the cathode powder, could be regarded as the important factor for the excellent performance of the Li1.27Cr0.2Mn0.53O2layered material. The results demonstrated that the cathode material prepared by our approach is a good candidate for lithium-ion batteries.Keywords:cathode material;X-ray diffraction;Cr3+/Cr6+redox pairs;specific capacity;cycling performance