Graphene is a stable two-dimensional material with outstanding properties, such as good mechanical strength, high electrical and thermal conductivity. It can be potentially used in catalytic processes, polymer nanocomposites and electrochemical devices, such as: supercapacitors, batteries, solar and fuel cells. Fuel cells are expected to become the technology of the future, especially for energy conversion. Among the various types of fuel cells, much attention is paid to ethanol fuel cells due to easy availability of ethanol, safe storage and the use of relatively inexpensive and non-noble metal catalysts. A key component of fuel cells is the ion exchange membrane, which provides ionic conductivity and acts as a separator between the anode and cathode. The commercialization of ethanol fuel cells is currently still limited due to the slow kinetics of anodic electrochemical reactions and the crossover of ethanol across the membrane. To this end, new membranes with improved properties need to be developed.
As part of my master's thesis I used chemical procedures to produce graphene derivatives from multiwalled carbon nanotubes (MWCNT). By using characterization methods, such as scanning electron microscopy (SEM), elemental analysis (CHN and EDS) and BET-specific surface analysis, I analyzed the properties of the obtained materials. By introducing nitrogen doped graphene (N-graphene) into chitosan, composite membranes with improved properties were fabricated. To measure the electrical resistance of the membranes, I developed and tested a suitable electrochemical cell. The ionic conductivity of the membranes was determined by electrochemical impedance spectroscopy (EIS). The most promising results were shown by membranes with 0,04 wt. % N-graphene, as they achieved the highest values of ionic conductivity.
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