Facile synthesis of 2D graphene oxide sheet enveloping ultrafine 1D LiMn2O4 as interconnected framework to enhance cathodic property for Li-ion battery
Cubic spinel lithium manganese oxide (LiMn2O4) has been able to attract a great deal of attention over the years as a promising cathode material for large scale lithium ion batteries. Here a facile hydrothermal route followed by solid state reaction is developed using as grown ultrafine alpha-MnO2 nanorods to prepare one dimensional LiMn2O4 with 10-50nm diameters. To enhance the cathodic property of these nanorods, a unique synthesis technique of heat treatment is developed to grow 2D graphene oxide sheet enveloping 1D LiMn2O4 as interconnected framework. This nanocomposite 3D porous cathode exhibits a high specific charge capacity of 130mAh/g at 0.05C rate and Coulombic efficiency of about 98% after 100 cycles in the potential window of 3.5 to 4.3V versus Li/Li+ with promising initial charge capacity retention of about 87%, and outstanding structural stability even after 100 cycles. Enhancement in the lithiation and delithiation processes leading to improved performance is likely to have its origin in the 2D conducting graphene oxide sheets. It allows for decreasing the Mn dissolution, improve the electron conductivity and reduce the Li-ion path diffusion inside the favourable morphology and crystallinity of the ultrafine 1D LiMn2O4 nanorods, giving rise to a promising cathode nanocomposite.