MnO Nanoparticles Sandwiched within 3D Graphene-Based Hierarchical Architecture for Efficient Lithium Storage

Manganese monoxide (MnO) has drawn considerable attention as anode candidate for lithium-ion batteries (LIBs) due to its high theoretical capacity of 755.6 mAh g^-1 (over twice as much as graphite) and relatively low voltage hysteresis. However, some challenging issues such as poor cyclic performance and inferior rate capability caused by the limited reaction kinetics, severe particle agglomeration of MnO, and large volume expansions during cycling still hampered its commercial implementation. Herein, we developed a rational design, in which MnO nanoparticles are sandwiched within 3D graphene-based N-doped carbon (NC) networks, which is denoted as NC/MnO/rGO. When investigated as anode for LIBs, the well-designed NC/MnO/rGO nanohybrid demonstrates high reversible capacity (1360 mAh g^-1 at 0.2 A g^-1 over 150 cycles), excellent rate capability, and good cyclability (648 mAh g^-1 at 2 A g^-1 without fading over 600 cycles). In addition, the mechanism of electrochemical reaction for the NC/MnO/rGO anode is further investigated by conducting cyclic voltammetry under different cutoff voltage ranges to explain the capacity increasing phenomenon upon cycling.