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Herein we fabricated a series of flexible electrode materials with nickel foam as a partly self-sacrificial template by an in situ growth solvent thermal method.

A polyacrylonitrile (PAN) precursor fiber of a special grade for preparing carbon fibers was modified by the impregnation of an aqueous KMnO 4 solution. The effects of the modification on the lateral and morphology structure, related to the crystalline properties of both the precursors and preoxidized fibers, such as the orientation index, crystal size, and crystallinity index, were measured by wide-angle X-ray diffraction. For both modified and original PAN fibers, a comparative study of the changes of the elemental content during the process of preoxidation, the relations between the thermal stress and heat-treatment temperature, and the effect of the modification on the skin/core structure of a preoxidized fiber were also introduced by the use of elemental analysis, optical microscopy, and so on. The modification of KMnO 4 was demonstrated to increase the density, increase the crystallinity index, increase the preferred orientation index, and decrease the crystal size for a modified precursor fiber and for a preoxidized fiber developed from a modified precursor fiber after a different heat-treatment temperature. KMnO 4 also showed a catalytic action, accelerating the rate of preoxidation and reducing the time of thermal stabilization; this improved the homogenization of the cross-section structure and led to an improvement in the tensile strength of 15-20% and an improvement in the elongation of 20 -30% in the resulting carbon fibers.

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