LAUSR

Abstract Combining the surface modification with bulk doping by ZnO, the co-modification strategy was applied to improve the structural stabilities and electrochemical properties of the layered Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode materials. The spherical morphology with a surface coating layer and evenly distributed Ni, Co, Mn, and Zn elements for the co-modified samples were demonstrated by the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images, together with the corresponding elemental mapping. Although the Ni2+ was increased near the surface, according to the X-ray photoelectron spectroscopy (XPS) results, the Li+/Ni2+ cation mixing remained constant based on the Rietveld refinement results. The electrochemical demonstrated its superior capacity retention with respect to the unmodified sample, especially in the first 300 cycles. Meanwhile, the co-modified sample also exhibited slower discharge voltage decay with inhibited electrode polarization, as well as lower interfacial resistances and faster Li-ions diffusion kinetics after 200 cycles in comparison with the pristine sample. The structure and morphology analysis results of the cycled electrodes revealed that the co-modified strategy of ZnO efficiently alleviates the structural pulverization of the spherical particles and successfully avoids the irreversible phase transformation towards the rock-salt phase. These results confirmed that the co-modified strategy of Zn2+ bulk doping and ZnO surface coating is highly conducive to the improvement of structural stabilities and electrochemical properties of the layered LiNi0.8Co0.1Mn0.1O2 cathode materials.