Developing the processing stages of carbon fiber composite paper as efficient materials for energy conversion, storage, and conservation

Abstract

Carbon is a wonder material and has served the mankind since the inception of civilization in a variety of ways. Among its different forms, carbon fibers are especially known for their conductivity and favorable strength to weight ratio. Here the development of PAN based carbon fibers embedded in a matrix material followed by pyrolysis to form a fibrous C/C composite has been discussed. The processing of carbon paper has been divided into four steps, with the product of each stage used separately for different energy applications. (1) Carbon fiber preform has been used as a filler to achieve high strength in bipolar plates for PEM Fuel cells (energy conversion). Flexural strength of nearly 80 MPa has been achieved as compared to 40 MPa of the commercially available Schunk plate, Germany. (2) Resin impregnated preform, i.e. the Green composite paper has been employed as an energy efficient heating element (energy conservation). This has been further fabricated as a room heater, which works at <200 W of power as compared to 1–2 kW ingested by the commercial heaters. (3) The Carbonized paper, worked well as a free standing anode for rechargeable Li-ion batteries (energy storage). It delivers a discharge capacity of 225 mAh/g @ 0.2C rate with excellent cycling performance (>500 cycles). The (4) Graphitized carbon paper has proved to be an excellent electrode (anode and cathode) backing material for PEM Fuel cell. 25% hike in the peak power density of unit PEM FC has been achieved while employing CNT incorporated NPL carbon paper as compared to while using Toray carbon paper of Japan and tested under similar conditions. This in turn is attributed to the unique properties acquired by the material with subsequent processing at each stage which has been discussed in detail.