Nanomaterial-functionalised carbons for next-generation supercapacitor electrodes

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To effectively utilise intermittent sustainable energy sources, and to reduce the current over-capacity in energy generation systems, necessary to meet 'peak demand', we must develop efficient energy storage technologies. Supercapacitors will play a key role in the future flexible energy grid (as well as in automotive and personal electronics), due to their ability to quickly charge/discharge (enabling high power output) and their potentially lengthy lifespans. However, current technologies suffer from low energy densities (~ 5 W h kg-1), meaning very large devices must be constructed if high energy capacity is required (e.g. in cars/busses). This deficiency is partially due to the materials from which the electrodes are constructed, commonly activated or porous carbons, which have low conductivity, low packing density, and poor inter-particle interconnectivity. The materials I will develop in this Fellowship will provide elegant and practical solutions to these problems. I will, for the first time, scalably nano-texture the surfaces of bulk carbons (e.g. activated carbons) with nanomaterials, improving their conductivity and connectivity, as well as efficiently increasing their surface area and introducing highly active pseudocapacitive materials. This will dramatically improve the energy storage performance of these materials. I will achieve this through the utilisation of liquids containing charged nanomaterials that can be manipulated onto the carbon surfaces using highly scalable, low-cost methods such as electrodeposition. Importantly, the deposition strategies will negate detrimental nanomaterial re-stacking and agglomeration, thus harnessing the beneficial properties of individualised nanomaterials. This cross-disciplinary work will bring together three departments at University College London (UCL). It will exploit the wide-ranging synthetic and analytical facilities in Dept. of Chemistry, the pioneering facilities for the creation of charged nanomaterial solutions in the Dept. of Physics & Astronomy and the world-class electrochemical manufacture and testing equipment in the Electrochemical Innovation Lab. This combination makes UCL the ideal location for this work. These facilities will allow both electrochemical- and chemical-deposition of charged nanomaterials to be developed in parallel and optimised for nano-structures including carbon nanotubes, graphene and MoS2. By controllably depositing these materials I will be able to control the surface morphology and redox-activity of surfaces, and therefore create materials which can be tuned. These will be extensively tested in lab-scale supercapacitor devices and the most successful will be scaled to produce an industrial demonstrator with my industry partner. Through careful structural investigation of the hybrid-materials, and the electrodes they produce, using advanced microscopy, phase-contrast X-ray tomography and small-angle X-ray scattering techniques, I will elucidate their structure-performance relationships.