Graphene wrapped ordered LiNi(0.5)Mn(1.5)O(4) nanorods as promising cathode material for lithium-ion batteries

LiNi(0.5)Mn(1.5)O(4) nanorods wrapped with graphene nanosheets have been prepared and investigated as high energy and high power cathode material for lithium-ion batteries. The structural characterization by X-ray diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy indicates the LiNi(0.5)Mn(1.5)O(4) nanorods prepared from β-MnO(2) nanowires have ordered spinel structure with P4(3)32 space group. The morphological characterization by scanning electron microscopy and transmission electron microscopy reveals that the LiNi(0.5)Mn(1.5)O(4) nanorods of 100–200 nm in diameter are well dispersed and wrapped in the graphene nanosheets for the composite. Benefiting from the highly conductive matrix provided by graphene nanosheets and one-dimensional nanostructure of the ordered spinel, the composite electrode exhibits superior rate capability and cycling stability. As a result, the LiNi(0.5)Mn(1.5)O(4)-graphene composite electrode delivers reversible capacities of 127.6 and 80.8 mAh g(−1) at 0.1 and 10 C, respectively, and shows 94% capacity retention after 200 cycles at 1 C, greatly outperforming the bare LiNi(0.5)Mn(1.5)O(4) nanorod cathode. The outstanding performance of the LiNi(0.5)Mn(1.5)O(4)-graphene composite makes it promising as cathode material for developing high energy and high power lithium-ion batteries.