Promoting the electrochemical performance of Li-rich layered Li1.2(Ni1/6Co1/6Mn4/6)0.8O2 with the in-situ transformed allogenic spinel phase

To promote the electrochemical performance of Li-rich layered cathode material Li1.2(Ni1/6Co1/6Mn4/6)0.8O2, the allogenic spinel@Li-rich (1-y)[Li1.2(Ni1/6Co1/6Mn4/6)0.8O2]core∙y[Lix(Ni1/6Co1/6Mn4/6)2O4]shell are developed by the in-situ phase transformation method. The allogenic structure of the composites was characterized by X-ray powder diffraction, Raman spectroscopy, HRTEM and SAED. The obtained allogenic electrodes exhibit better initial Coulombic efficiency, higher reversible capacity and capacity retention than pristine Li-rich layered oxide. Electrochemical tests show that the electrochemical properties of the cathode material are best when the ratio of the spinel component is 3%. After 120 cycles at a rate of 0.2C, excellent reversible capacity (246 mAh g-1) and good capacity retention (94%) were obtained. Moreover, the rate performance of allogenic spinel@Li-rich composites has also been greatly improved. In particular, the sample with 3% spinel composition maintained a high discharge capacity ...