New insights into improving electrochemical performances of LiNi0.5Mn0.5O2 cathode material by Li2ZrO3 coating and Zr4+ doping

The poor electrochemical performances of LiNi0.5Mn0.5O2 prevent its wide adhibition. Herein, the synergistic effects of Li2ZrO3 coating and Zr4+ doping were used to enhance the electrochemical performances of LiNi0.5Mn0.5O2. Li2ZrO3 was evenly coated on the surface of LiNi0.5Mn0.5O2 successfully by a syn-lithiation strategy and small partial of Zr4+ was doped into the LiNi0.5Mn0.5O2. The results of the structure measurements indicated that Zr4+ doping cannot only lower the degree of Li/Ni cation maxing, but also improve the stability of the structure. The outcome of scanning electron microscope (SEM) suggests that the thin coating layer of Li2ZrO3 can reduce agglomeration. Moreover, X-ray photoelectron spectroscopy (XPS) indicated that Li2ZrO3 coating layer can reduce the side reaction in the interface between the cathode and the electrolyte. Therefore, the capacity retention of the 3 mol% Li2ZrO3@LiNi0.5Mn0.5O2 (“@” stands for “was coated on the surface of”) electrode is 22% higher than that of the pristine electrode (100.41% vs.78.22%). After mechanism analysis, we found the synergistic effects of Zr-doping and Li2ZrO3 coating can effectively lower the degree of Li/Ni cation mixing, stop polarization, retard voltage degradation, and decrease resistances.