: Lithium ion batteries are ideal power sources for portable electronic devices and electrical vehicles. The carbon anode presently used in commercial lithium ion batteries has a relatively low capacity. It's required that the capacity of anode materials verge on 1000 mAh/g. On other hand, these materials must have low cast and be available. Manganese oxides materials are a good choice that used as anode and cathode materials in lithium ion batteries. Mangense oxides materials have high capacity and good cyclic behavior but they suffer from low conductivity and high capacity lost in first cycle due to conversion reaction with lithium. To solve this problem, active carbon nanofiber/manganese oxide composite are used. Active carbon nanofibers are produced via electrospinning from polyacrylonitril/dimethylformamid solution using a homemade electrospinning setup and then pyrolyzed in N 2 atmosphere at 850°C. The diameters of carbon nanofibers are varied from 150 to 250 nanometer as revealed by scanning electron microscope (SEM). Manganese oxides are deposited on active carbon nanofibers surface by electroless from an aqueous permanganate solution and influence of permanganate solution pH and deposition time on thickness, morphology and uniformity of deposited manganese oxide are surveyed. It's showed that the pH plays a very important role in determining the uniformity and kinetic behavior of deposited manganese oxide and at nearly neutral pH, the self-limiting redox reaction of carbon nanofibers substrates with permanganate produces conformal nanoscale manganese oxide deposits throughout the nanofibers network. The manganese oxide coating contributes additional capacitance to the carbon nanofibers. Such bare carbon nanofibers produce 190 mAh/g capacitance at first cycle while the capacity of carbon nanofibers/manganese oxide composite was 850 mAh/g at first cycle. One of the electrode materials degradation mechanisms in lithium ion batteries is fracture of electrode particles due to intercalation-induced stress. At this research a model with the analogy to thermal stress modeling is proposed to determine intercalation induced stress and its effect on concentration profile. Intercalation-induced stress is calculated within cylindrical and spherical geometry with a constant diffusion flux assumed at the particle surface. It was found that the intercalation induced stress in cylindrical geometry is less than the spherical geometry. Simulation results show that whatever the charge/discharge rate and particle size be lower the intercalation induced stress will be lower. Key words: Lith ium ion battery, carbon nanofiber, electrospinning, manganese oxide, electroless, diffusion induced stress.
