A carbon nanofiber‐based electrode, exhibiting a large accessible surface area (derived from the nanometer‐sized fiber diameter), high carbon purity (without binder), relatively high electrical conductivity, structural integrity, thin web macromorphology, a large reversible capacity (ca. 450 mA h g–1), and a relatively linearly inclined voltage profile, is fabricated by nanofiber formation via electrospinning of a polymer solution and its subsequent thermal treatment. It is envisaged that these characteristics of this novel carbon material will make it an ideal candidate for the anode material of high‐power lithium‐ion batteries (where a high current is critically needed), owing to the highly reduced lithium‐ion diffusion path within the active material.

Here we demonstrated the ability to fabricate ultra-fine carbon fibers through electrospinnig of the polymer blends of the polyacrylonitrile (PAN) and polyamic acid (PAA) and the subsequnt thermal treatment. The good spinnability of the polymer blends was achieved by reducing the solution viscosity with the addition of PAN. There was a close correlation between the fiber diameter developed in the spinning process and the physical properties of the carbonized fibers; the smaller in fiber diameter gave rise to the higher crystallinity of the single carbonized fiber and, furthermore, the higher electrical conductivity and mechanical strength of the carbonized fiber web. High anisotropy in mechanical strength of the carbonized fiber webs was ascribed to the partial alignment of fibers along the winding direction in the electrospinning process.

Chemically reduced solid-state mesophase pitch carbon fibers below 1000 o C in a flow of hydrogen gas was heat treated up to 3000 o C in an argon atmosphere in order to evaluate the effect of hydrogen on the graphitization behavior. Major phenomena observed during the reduction process are chemical transformation from an ether to a hydroxyl group (corresponding to the rupture of the C-O-C bond) and their subsequent evolution as gases.Finally, oversupplied hydrogen might be utilized to satisfy the dangling bond. For sample heat treated at 3000 o C, the low crystallinity indicates that hydrogen atoms covalently bonded to the end planes of graphitic layers act as an effective barrier to crystallite growth.

Milled mesophase pitch-based carbon fiber (mMPCF) was applied as a polarizable electrode for electric double layer capacitors (EDLCs). The mMPCF showed quite different activation behavior between physical and chemical activation methods. The effect of the KOH mixing ratio was examined and the influence on the asymmetric lattice structure also was considered. Furthermore, hydrogenation effect on the capacitance behavior is also shown . The reduction reaction by hydrogen did not affect the pore structure which material has, but it was effective to remove only oxygen containing functional group which exists in the surface. Hydrogenation was effective to improve the most important characteristic in practical application, such as cycle stability, coulomb efficiency .

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