The MnO@N-doped carbon composite derived from electrospinning as cathode material for aqueous zinc ion battery

Manganese-based oxides are considered as one of the most attractive cathode materials in aqueous zinc ion battery. However, the poor cycleability, inferior rate capability and associated with the ambiguous energy storage mechanisms seem to hinder its practical application. Herein, nitrogen-doped carbon-coated MnO (MnO@N-C) composite fibers were fabricated directly through an in situ strategy of electrospinning method, followed by two-step annealing processes. The results show that the cycling performances and rate capability of the as-prepared composite of MnO@N-C at 500 degrees C with graphite foil as the current collector (MnO@N-C-500-GF) arc much better than that with stainless steel mesh (MnO@N-C-500-SSM). It delivers the reversible capacity of 176.3 mAh g(-1 )even after 200th cycles at 500 mA g(-1 )and 100.5 mAh g(-1 ) at large current density of 1.2 A g(-1 ) for the former. The electrochemical kinetics reveals that all the electrode reaction are mainly contributed by a diffusion-controlled process and partially dictated by the surface-controlled capacitive behavior. Significant insight into the energy storage mechanism is confirmed by ex situ X-ray diffraction. The detailed phase evolution process during the charge and discharge process indicates that MnO@N-C cathode with high reversibility and cycling stability experiences an insertion/extraction process of Zn2+ along with a dissolution/deposition mechanism due to Mn2+ dissolution.