Highly Conductive Carbon Aerogels for Battery Applications

Kurzfassung

Carbon aerogels are well known open porous solid materials first introduced by Richard Pekala in 1989 [1]. Usually carbon aerogels are derived by pyrolysis of organic precursors such as resorcinol-formaldehyde, melamine-formaldehyde [2], and other organic precursors. Due to their high inner surface area of about 2000 to 2500 m²/g, high pore volume of about 3 to 5 cm³/g [3] carbon aerogels have a broad field of applications. Caused by their electrical conductivity of up to 10² S/m [4], the field of electrical applications extends from super-capacitors to rechargeable lithium based batteries. High electrical conductivity of carbon aerogels is necessary for battery applications. In order to improve the electrical conductivity, additives such as different graphite powder can be homogeneously embedded to carbon aerogels. Due to low viscosity and long time gelation, it is difficult to produce such composites by simply mixing additives into the resorcinol-formaldehyde sol. In our study, we compare two synthetic routines, first based on resorcinol-formaldehyde (RF) and the second on resorcinol-melamine-formaldehyde (RMF), for synthesis of carbon aerogel composites. Due to adjustable viscosity of RMF-sol, composites with homogeneously distributed additives could be successful synthesized. Various additives with different amounts have been tested. The received composites were characterized in terms of skeletal density, specific surface area, micropore and mesopore volume and size distribution and most important electrical conductivity as these are critical parameters for the use in electrochemical applications. Within the presentation we will report on the actual research and development of carbon aerogel composite materials and will focus on its benefit on new concepts in batteries applications.