Carbon Materials and Electrochemical Energy Applications
Regarding todays environmental challenges carbon may be the key elemental component, usually blended into notations such as “carbon cycle” or “carbon footprint”. Interestingly, not being used as “fossil fuel”, carbon materials also considerably contribute to the field of sustainable energy. They are central in most electrochemical energy-related applications, i.e. they also help to generate, store, transport, and save energy.
Nanostructured carbon is already used in fuel cells, conventional batteries and supercapacitors, but is expected to play an even much bigger role in new forthcoming energy schemes. There is a huge variety of precursors and methods to produce functional carbons with different properties. Ideally, natural biomass, created via the photosynthetic conversion of CO2 from the environment, can serve as a base feedstock for the generation of such long lasting materials, which store carbon in concert with sustainable principles such as energy and atom economy and low toxicity.
We develop new strategies to synthesize novel nanostructured and functional carbon-rich materials and derivatives thereof. Our first aim is to generate materials leading to improved performances in electrochemical applications. The second aim is to do that sustainably.
Generally, the production of porous carbons can be subdivided into top-down and bottom-up procedures. In the top-down or activation method pores are developed by physical or chemical “etching” resulting in porous products. The etching is influenced by the chemical composition of the primary carbon, i.e. can modify the final composition and is accompanied with rather high mass losses.
The bottom-up process allows for the intentional and homogeneous creation of chemical compositions, such as the amount of heteroatom doping. The design of morphologically defined carbons here usually makes use of so-called templates, which can be structure directing agents or solid scaffolds, which can be employed in a nanocasting process. Most of the established processes possess disadvantages, such as template synthesis and hazardous template removal. Additionally in most cases the templates cannot be reused.
We try to reduce the number of steps towards the final carbon material by employing sol-gel principles e.g. to the hydrothermal carbonization (HTC) of carbohydrates1 and to the ionothermal carbonization of specific ionic liquids.2
These bottom-up approaches, starting from homogeneous mixtures, allow for the variation of chemical compositions independent of the surface area/porosity properties. The only requirements are adequate additives e.g. containing the desired heteroatoms.3-5 The final modification can lead to impressive performances in electrochemical applications like electrocatalysis and supercapacitors.3,6-8
Well-defined “organic” porous materials, such as covalent organic frameworks (COFs) may help to understand the details of the material formation and performance serving as intermediate and model compounds, respectively.
A final translation of the as-obtained properties to more sustainable and cheap biomass-derived precursors finally is our ambition.
- Fellinger, T. P.; White, R. J.; Titirici, M. M.; Antonietti, M. Advanced Functional Materials 2012, 22, 3254.
- Fechler, N.; Fellinger, T.-P.; Antonietti, M. Advanced Materials 2013, 25, 75.
- Wohlgemuth, S. A.; Fellinger, T. P.; Jaker, P.; Antonietti, M. Journal of Materials Chemistry A 2013, 1, 4002.
- Fellinger, T. P.; Su, D. S.; Engenhorst, M.; Gautam, D.; Schlogl, R.; Antonietti, M. Journal of Materials Chemistry 2012, 22, 23996.
- Fechler, N.; Fellinger, T. P.; Antonietti, M. Chemistry of Materials 2012, 24, 713.
- Fellinger, T. P.; Hasche, F.; Strasser, P.; Antonietti, M. Journal of the American Chemical Society 2012, 134, 4072.
- Hasche, F.; Fellinger, T. P.; Oezaslan, M.; Paraknowitsch, J. P.; Antonietti, M.; Strasser, P. ChemCatChem 2012, 4, 479.
- Yang, W.; Fellinger, T.-P.; Antonietti, M. Journal of the American Chemical Society 2010, 133, 206.