Synergetic action of doping and coating on electrochemical performance of lithium manganese spinel as an electrode material for lithium-ion batteries

Spinel LiMn2O4 and multidoped spinel LiMn1.9Co0.025Cr0.025Ni0.025Fe0.025O4 were synthesized by the glycine-nitrate method and coated with lithium borosilicate (LBS) in order to enhance the electrochemical performance at room temperature. The structure and electrochemical performance of all samples were characterized by inductively coupled plasma-mass spectrometer (ICP-MS), X-ray diffraction (XRD), differential thermal analysis/thermogravimetry (DTA/TG), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and galvanostatic charge-discharge measurements. The XRD analysis shows that the samples exhibit a pure spinel phase. The SEM results indicated that LBS particles had encapsulated the surface of the undoped and multidoped LiMn2O4 without causing any structural change. The charge-discharge tests showed that LiMn1.9Co0.025Cr0.025Ni0.025Fe0.025O4 displays better cycling performance than the pristine LiMn2O4 at room temperature. However, in the same conditions, LBS-coated LiMn1.9Co0.025Cr0.025Ni0.025Fe0.025O4 and LiMn O-2(4) have better cycling performance than uncoated samples. The results suggest that multidoped and LBS-coated LiMn2O4 could develop into a promising cathode material for lithium ion batteries.