Morphological control of LiNi 0.8 Mn 0.1 Co 0.1 O 2 lithium-ion cathodes using biotemplating Ryan Emmett, Rebecca Boston University of Sheffield, UK By 2030, all new cars in the UK will be electric vehicles, EVs, in order to reduce the 27% of UK emissions the transport industry is contributing to climate change [1] . Despite the impending change, Li-ion cells used by industry still face challenges with range and high cost (relative to petrol vehicles). Current solid-state methods for producing Li-ion cells are also expensive due to high material costs, synthesis temperatures, and synthesis time. High nickel cathodes like LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathodes at an 8:1:1 ratio (NMC811) investigated here, may be used to improve overall capacity (and therefore range) but causes low capacity retention and structural instability due to mixing of the nickel and lithium. This mixing can be reduced by altering the particle morphology to that which restricts structural rearrangement. The altered particle morphologies can be synthesised using biotemplating, an emergent synthesis technique, which produces improved capacity retention and cycling while also reducing synthesis temperatures and time. By dissolving organic long-chain polysaccharides (e.g. dextran, sodium alginate, or κ-carrageenan) with precursor metal ions in solution, homogenous mixing and chelation can occur. Biotemplate functional groups are substituted with precursor metal ions, preventing recrystallisation of the precursor materials. The templates are then combusted at elevated temperatures, with the high degree of mixing leading to shorter reaction pathways, enabling products to be synthesised faster and at lower temperatures. In this poster I will demonstrate that by using different biotemplates, different particle morphologies can be produced. Biotemplating results in nanoscale, individual primary particles, with dextran (sugar) resulting in plate-like morphologies, and the seaweed derivatives sodium alginate or κ-carrageenan giving anisotropic or nanowire morphologies. My work shows nanowires form in the presence of lithium carbonate impurities or lithium-manganese-oxide phases, potentially reducing capacity retention by reducing cathode structural instability. NMC811 nanowires have been observed using a lower proportion of lithium, indicating lithium has an effect on nanowire formation. The manipulation of particle morphology along with lower synthesis times and temperatures would allow for cheaper, higher performance lithium-ion cells in EVs, benefiting both industry and the consumer, while also reducing emissions from transport in the UK. References 1. Department for Business, Energy &Industrial Strategy. 2021. 2019 UK Greenhouse Gas Emissions, Final Figures. February 2. Accessed June 3, 2021. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/ file/957887/2019_Final_greenhouse_gas_emissions_statistical_release.pdf.
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