Preparation And Electrochemical Performance Of MnO_x/C Composite Fiber Membranes

With high energy density,no memory effect and be environmental-friendly,lithium ion batteries are always hot research area in secondary batteries.It's meaningful to find a material with low-cost,long cycle life and high specific capacity,because electrode materials can influence the performance of battery directly.MnOx,as a transition metal oxide,become a important material of lithium ion batteries with high specific capacity,low-cost and environmental-friendly.However,the rapidly decrease of capacity and cycle life from the volume expansion and poor electrical conductivity,which usually leads to mechanical damage during charge and discharge processes.This paper focus on control the materials microstructure by electrospinning to accommodate the volume of charge/discharge processes and thus with enhanced the electrochemical performance.Preparation of PAN fiber membrane by electrospinning technology,with manganese acetylacetonate as the source of manganese,after carbonized process,obtain the MnOx/C self-supporting flexible fiber membrane with different content of manganese.Study of electrochemical performance of the products,it shows that the material which content of manganese acetylacetonate is 70%of polyacrylonitrile shows the best performance,a specific capacity of 475.6 mAh g-1 is obtained at a current density of 500 mA g-1 after 200 cycles,which is 91.6%of the initial specific capacity,exhibited the best performance of lithium ion storage.Using coaxial electrospinning of PAN and PMMA,with one-step calcination and two-step calcination to obtain hollow tubular carbon fibers with MnO nano-particle,the MnO/C composite was tested as an anode material for lithium ion batteries.That shows an initial coulombic efficiency of 57.85%of one-step calcination OC-MnO/C and after 100 cycles at a current density of 100 mA g-1,specific capacity of 607.3 mAh g-1.The TC-MnO/C have an initial coulombic efficiency of 66.70%,and after 100 cycles at a current density of 100 mA g-1,specific capacity of 640.4 mAh g-1 were retained.To summarize,The OC-MnO/C and TC-MnO/C materials showed good lithium storage properties as anode materials for LIBs.Furthermore,TC-MnO/C composite is slightly better than OC-MnO/C composite.