Sustainable biotemplated syntheses and charaterisation of nanoparticulate sodium-ion battery cathode materials

Climate change is a critical global issue: shifting away from releasing CO2 by burning fossil fuels is vital. Future electricity grids will be decentralised and reliant on renewable sources (wind, wave, solar), where fluctuations in energy production cause issues matching supply with demand, raising the urgent need for cheap, effective, sustainable energy storage solutions. In this project, we will develop our research on novel biotemplated syntheses of next-generation sodium-ion battery (NIB) cathode materials for grid-scale storage and load-leveling applications to ensure consistent and secure electricity supplies. This is a pressing concern for both sustainability and performance. Traditional battery materials synthesis needs high temperatures (>800°C), making production energy costs a major sustainability issue for industry. Alternatives to NIBs based on lithium-ion battery (LIB) technologies are well-known but Li is expensive and relatively scarce. Safety and poor cycling concerns also make Li unsuitable for large grid-scale applications. NIBs are an attractive solution, without the major issues of LIBs, but the electrochemical performance of current NIB materials is too poor for applications. Sodium is a large heavy ion; migration through dense crystals structures is difficult. New, improved materials are needed, with nanoscaling being a likely candidate. This approach was used for LiFePO4 cathodes, later commercialised for power tools and electric vehicles despite the low electronic conductivity and slow Li diffusivity in LiFePO4. It is timely and important that NIB materials be similarly investigated. Biotemplated syntheses are an emergent, flexible set of methodologies to rapidly form novel nanoscale crystal shapes in oxides. Atomically mixed metal ion-biotemplate composites are formed by ion uptake from solution, and give unprecedented control of crystal formation as the template is combusted. Such approaches give significant advantages over traditional high-temperature routes: reaction of atomically homogeneous mixtures creates short ionic diffusion distances between reagents, promoting rapid, low-temperature reactions. Biotemplates give unparalleled control of particle shape and size on the nanoscale. Creation of nanoparticles (using sugar), nanowires (using seaweed derivatives) etc. may yield electrode materials with shorter, faster Na-ion migration routes, potentially resulting in improved specific capacities, better structural stability on removal of Na, and improved rate capabilities via increased surface and electrolyte/electrode contact areas. This project will enable a new interdisciplinary collaboration: crystal chemistry and ionic diffusion mechanisms (NRM), emergent biotemplating syntheses and consolidation techniques (RB), and electrochemical testing of NIB materials (PH): the doctoral scholar will benefit from all three, creating a uniquely skilled researcher able to advance the NIB field.

Silvija Zilinskaite
Silvija Zilinskaite
student

I graduated from University of Sheffield last summer in Material Science and Engineering. I am now part of the Energy Storage and Applications CDT at Sheffield which is run in collaboration with the University of Southampton. I am coming towards the end of my training year, where I had the opportunity to learn about various energy storage technologies, future electricity grid topologies and also dabbled in a bit of social science. I will begin my PhD project this summer joint between the CDT and ICON, where I will focus on biotemplating synthesis of cathode materials for sodium-ion batteries, supervised by Dr Rebecca Boston and Dr Nik Reeves-McLaren. The aim of the project is to improve electrochemical properties of the Na cathode materials by controlling the morphology and particle size growth through the selection of biotemplate and reaction conditions.

Rebecca Boston
Rebecca Boston
supervisor

Rebecca is a 2016 Lloyds Register Foundation / Royal Academy of Engineering Research Fellowship in the control of nanostructures in functional oxides. Her current research interests include functional ceramics for capacitors, thermoelectrics and batteries. She joined the Department in 2014 as a Postdoctoral Research Associate with Professor Ian Reaney and Professor Derek Sinclair. Prior to this, Rebecca completed her PhD with Dr Simon Hall in the School of Chemistry at the University of Bristol through the Bristol Centre for Functional Nanomaterials.

Nik Reeves-McLaren
Nik Reeves-McLaren
supervisor

Nik Reeves-McLaren obtained his BSc (Hons) in Chemistry with New Materials Technology from The University of Aberdeen in 1999, before moving to The University of Sheffield where he undertook a PhD on "Novel Cathode and Anode Materials for Rechargeable Lithium-ion Batteries”. He was appointed as XRD Research Facility Manager in November 2003, and promoted to Research and Teaching Fellow in 2014.

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