Preparation And Electrochemical Performance Characterization Of Electrospinning Composite Nanofibers

The Lithium-ion battery is an environmental friendly storage device.Lithium-ion batteries have attracted a lot of attention,because of its high energy density, long cycle life, no memory effect, low cost and small self-discharge. As crisis of energy and environment, and increase of portable equipment in daily life, more and more high lithium-ion performance is required. Due to the excellent performance, nano materials have been used in the development of lithium-ion.Electrospinning is one of methods to prepare one dimensional nano materials. Electrospinning has been widely used in many fields, because of its easy operation and low cost. So inorganic nanofibers, used bfor anode materials of lithium-ion batteries, can be prepared by electros pinning. The ways to prepare C/Ni composite nanofibers by single and Co-axial electrospinning technology, have been described in detail. The crystal structure and merphologies of as-prepared fibers were characterized by SEM, TEM, XRD and TG methods. Electrochemical performance of as-prepared materials was measured by charge/discharge measurment at constant current. The detail content of this work is as follows:Nickel oxalate was synthetized by nickel acetate and oxalic acid. Nickel oxalate at different mass was added to PAN solution to make4mixed solutions with different percentage of weight, preparing nanofibers by electrospinning. Influence on morphology and structure by different content fo nickel oxalate has been discussed. The solution became unstable in the electros pinning process when the content of nickel oxalate in solute reached10%. PAN and PAN/nickel oxalate nanofibers were characterized by FTIR method, and carbon and carbon composite nanofibers,prepared by the calcination of as-prepared nanofibers,were characterized by XRD method. The result show that PAN/nickel oxalate composite nanofibers were prepared because of a OH absorption peak in FTIR, the C/Ni-NiO nanofibers were prepared because of nickel oxide not being fully reducted. The prepared nanofibers were assembled into analog cell to test its electrochemical performance. The result show that the electrochemical properties have been markedly improved after doping nickel oxalate.With nickel acetate as precursor, PAN/Nickel acetate and PVP solution with different concentration were equipped, respectively. Porous composite nanofibers was prepared by co-axial electrospinning, the formation mechanism of porous structure was discussed. The results show that structrual stability of nanofibers became variation in the calcining process because of rapid heating rate, as inner solution diffusion to outer solution, the core polymer was diffused to the shell,and the bubbles were produced in the calcination, face-centered cubic crystal nickel was formed as nickel acetate reduction was complete, and uniformly distributed in the fibers. Performance of porous carbon composite nanofibers was good in the battery performance test.