Manganese dioxide-anchored three-dimensional nitrogen-doped graphene hybrid aerogels as excellent anode materials for lithium ion batteries

The capacity of manganese dioxide (MnO2) deteriorates with cycling due to the irreversible changes induced by the repeated lithiation and delithiation processes. To overcome this drawback, MnO2/nitrogen-doped graphene hybrid aerogels (MNGAs) were prepared via a facile redox process between KMnO4 and carbon within nitrogen-doped graphene hydrogels. The three-dimensional nitrogen-doped graphene hydrogels were prepared and utilized as matrices for MnO2 deposition. The MNGAs-120 obtained after a deposition time of 120 min delivered a very high discharge capacity of 909 mA h g-1 after 200 cycles at a current density of 400 mA g-1, in sharp contrast to only 280 and 70 mA h g-1 delivered from nitrogen-doped graphene aerogels and MnO2. This discharge capacity is superior to that of the previously reported MnO2/carbon based hybrid materials. This material also exhibited an excellent rate capability and cycling performance. Its superior electrochemical performance can be ascribed to the synergistic interaction between uniformly dispersed MnO2 particles with high capacity and the conductive three-dimensional nitrogen-doped graphene network with a large surface area and an interconnected porous structure.