Efficient dispersion of carbon fibers by plant polysaccharide guar gum to achieve a uniform and strong carbon paper for supercapacitor electrode.

Abstract

Carbon paper features excellent electrical conductivity, lightweight, and corrosion resistance and is widely used in energy storage and conversion. However, conventional carbon paper is predominantly composed of short fibers (3 mm), leading to high brittleness and low mechanical strength. Due to the flocculation issues, the efficient dispersion of long carbon fibers (CF) still faces challenges. Herein, a natural polysaccharide guar gum is used for efficient dispersion of long CF by adjusting the wetting effect between the aqueous phase and CF interface. Attributed to the enhanced viscosity and decreased surface tension of the dispersion liquid, the agglomeration of CF is effectively prevented. Under the concentration of 0.6 wt% guar gum and 0.02 wt% CF, the formation of CF base paper is up to 70%, much higher than the commercial Toray carbon paper (~50%). After phenolic resin impregnation, hot pressing, and carbonization, the resulted carbon paper achieves good mechanical properties (7 MPa in tensile strength and 8 MJ/m3 in toughness), thermal stability (314 °C), gas shielding ability (0.0045 cm3/m2∙d∙Pa), and shows high electrical signal stability, and favorable charge transfer capabilities when used as supercapacitor electrode. Such simple and efficient method to achieve a uniform carbon paper demonstrates a promising strategy for high-performance supercapacitor electrode.

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