Freeze-drying preparation of MnO x /graphene nanocomposite as anode material for highly reversible lithium storage

Manganese oxides (MnO x ) as potential anode materials need support by porous carbonaceous materials to avoid its large volume change, pulverization and poor conductivity during lithiation and delithiation. However, the homogeneous distribution of MnO x particles onto graphene sheets (rGO) is still questionable, because both components have different densities and activity in solution. Freeze-drying technique has gained remarkable attention for the fabrication of porous nanocomposites. In this work, a homogeneous nanocomposite of MnO x /rGO is successfully synthesized by freeze-drying technique compared with MnO x /rGO sample synthesized by traditional drying method, and MnrGO-FD sample exhibits an improved rate performance and cyclic performance. It delivers 1446.4 mAh g −1 with Coulombic efficiency (CE) of 70.4% at the initial cycle and remains 1246.6 mAh g −1 with CE of 98.6% after 150 cycles at 0.1 A g −1 . Moreover, it delivers capacity of 729.1 mAh g −1 with CE of 99.3% at 1 A g −1 for 300 cycles. Benefiting from freeze-drying, MnO x nanoparticles are distributed on porous graphene framework and graphene buffers the volume expansion of MnO x and provides conductive channels between electrolyte and active materials.