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Liam Bird

Liam Bird

E-mail: llrb2<at>
Address: Cambridge Graphene Centre, Engineering Department,
University of Cambridge, 9, JJ Thomson Avenue, Cambridge, CB3 0FA

Liam Bird is is a research student working on the PHD project: 2D materials and Hard Carbon in Lithium Batteries.

His main supervisor is Dr Cate Ducati and his second supervisors are Prof. Andrea Ferrari and Prof. Vasant Kumar.

Lithium-sulfur (Li-S) batteries, able to store ~5 times the energy per unit weight as conventional lithium-ion batteries, have potential applications in transport, aerospace, and storage of renewably-generated electricity. However, sulfur's low electrical conductivity and the formation of insoluble lithium polysulfides (PS) throughout the conversion chemistry-based charge and discharge process result in poor capacity retention over successive cycles and at high charge/ discharge rates. Overcoming these challenges requires the development of host matrix for the sulfur cathode, to provide an electrically conductive network capable of constraining the sulfur and PS in electrical contact with the current collector.

Graphene is a promising candidate for use in host matrices in Li-S batteries, due to its high conductivity, high surface area, and compatibility with a range of scalable synthesis techniques. Functionalised graphene, including graphene oxide, provides additional opportunities for improved PS constraint via chemical interaction. This work investigates the effect of different graphene-related materials on the physical constraint of sulfur and PS and their distribution within the matrix over successive cycles. In-situ Raman spectroscopy is used to elucidate the concentration and type of PS in the electrolyte during cycling, electron microscopy with X-ray analysis techniques is used to track changes in the electrode structure and composition, and electrochemical testing of coin cells demonstrates the electrical potential and rate of reactions associated with each step of the charge/ discharge process. The findings from these experiments will be used to optimise graphene-based host matrices to decrease the internal resistance and self-discharge of Li-S cells and improve their capacity retention and rate capability, facilitating their more widespread application.

Liam is part of the Engineering department and is currently based in the Cambridge Graphene Centre, in the Electrical Engineering Division. He is a member of Darwin College.