Influence of Mn content on the morphology and improved electrochemical properties of Mn_3O_4|MnO@carbon nanofiber as anode material for lithium batteries

摘要

A series of composites manganese oxide/carbon with one-dimensional structure are synthesized using electrospinning. The phase composition, morphology and electrochemical performance of MnO_x/carbon are studied, which affected by the manganese concentration in precursor and subsequent carbonization conditions. The manufacture of MnO_x/carbon is composed of two steps including thermal stabilization (at 250 ℃ in air) and carbonization (at 700 ℃ in nitrogen). The main functional groups of samples are well identified by FT-IR spectra. The sample Mn33_3h with the lowest manganese content presents the construction structure which amorphous and/or nanosized MnO_x with smaller crystal size are grown and enwrapped in carbon fiber during carbonization. Mn33_3h presents the initial charge and discharge capacities of 1054.1 and 665.6 mAh g~(-1) and the discharge capacity at the 50th cycle remains 99.7% of that at the 2nd cycle. Beside the well rate capability at the range of current densities from 20 to 1000 mA g~(-1), Mn33_3h presents very good recovery ability after high rate cycling at 1000 mA g~(-1). The advantages of this composite structure as well as its high capacity make manganese oxide a very attractive candidate as an anode material for the next generation of rechargeable lithium ion batteries.