Enhanced electrochemical performance of Li 1.27 Cr 0.2 Mn 0.53 O 2 layered cathode materials via a nanomilling-assisted solid-state process

Abstract

Li 1.27 Cr 0.2 Mn 0.53 O 2 layered 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-NaFeO 2 structure. 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 Cr 3+ /Cr 6+ 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 -1 at 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 ·cm 2 ·s -1 ), caused by the mesoporous nature of the cathode powder, could be regarded as the important factor for the excellent performance of the Li 1.27 Cr 0.2 Mn 0.53 O 2 layered material. The results demonstrated that the cathode material prepared by our approach is a good candidate for lithium-ion batteries.