Carbon Paper with a High Surface Area Prepared from Carbon Nanofibers Obtained through the Liquid Pulse Injection Technique

To improve the performance of carbon paper used for applications such as electrodes for electrochemical devices and air filters, two types of long carbon nanofibers (CNFs) with average diameters of 20 and 49 nm were prepared by the liquid pulse injection (LPI) technique by adjusting reaction conditions. Carbon paper was made from the CNFs through a simple filtration process. The paper prepared from the CNFs with an average diameter of 20 nm (LPI-CNF(20) paper) was firm and flexible even though it was prepared without using any binders. LPI-CNF(20) paper also had a high surface area and showed a high electrical conductivity and a moderate gas permeability according to its void size. These properties are required for cathodes in the latest battery systems such as lithium-air batteries. In electrochemical experiments conducted to evaluate the performance of LPI-CNF(20) paper as a cathode, the paper showed a larger discharge capacity on the basis of the cathode weight than a conventional cathode (a commercially available carbon paper combined with a porous carbon), which indicated that it has a high potential to be used as a cathode in lithium-air batteries.