采用溶胶凝胶法制备了La0．7 Ca0．3 M nO3包裹LiNi0．5 M n1．5 O4正极材料。通过X射线衍射（XRD ）、扫描电子显微镜（SEM）、充放电测试、循环伏安以及交流阻抗测试研究了表面修饰对LiNi0．5Mn1．5O4材料的电化学性能的影响。研究结果表明：所制备的材料是纯相的尖晶石LiNi0．5 M n1．5 O4，La0．7 Ca0．3 M nO3颗粒均匀包裹在LiNi0．5Mn1．5O4表面。包裹的材料以2C倍率循环200次后容量保持110mAh／g ，容量保持率达到93．2％。La0．7 Ca0．3 M nO3包裹层有效保护电极材料，抑制了M n的溶解，提高了材料的电子导电性，降低了电荷传递电阻，减小极化，显著提高了材料的循环性能。%La0 .7 Ca0 .3 M nO3 -coated 5V spinel LiNi0 .5 M n1 .5 O4 as cathode w as prepared by mixing LiNi0 .5 M n1 .5 O4 pow‐ders and the sol -gel -drived La0 .7 Ca0 .3 MnO3 matrix ,followed by high -temperature calcinations .The effects of La0 .7 Ca0 .3 MnO3 -coating on the electrochemical performances of LiNi0 .5 Mn1 .5 O4 were investigated systematically by the charge/discharge testing ,cyclic voltammograms and AC impedance spectroscopy ,respectively .The obtained re‐sults showed that the La0 .7 Ca0 .3 MnO3 particles were uniformly deposited on the pure LiNi0 .5 Mn1 .5 O4 surface .Com‐pared with pristine LiNi0 .5 Mn1 .5 O4 ,La0 .7 Ca0 .3 MnO3 -coated material had much lower charge -transfer resistances . The results of electrochemical experiments demonstrated that the modified material exhibits remarkably enhanced electrochemical reversibility and stability .The discharge capacities remained 110mAh/g with capacity retention of 93.2% after200cyclesat2C.TheLa0.7Ca0.3MnO3coatinglayerprotectedthesurfaceoftheactivematerialsfromHF in the electrolyte during electrochemical cycling .As a result ,the electrochemical cycling stability was improved .
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