DESIGNING NANOPOROUS CARBONS AS ANODE MATERIALS FOR SODIUM ION BATTERIES

The UK faces the challenge to store energy from grid electricity generation (the current storage capacity is around just 3 GW, far short of the demand of around 20 GW). Greater capability (~10 GW) to store electricity will save the UK energy spend of up to £10 billion a year by 2050, and will provide flexibility for energy supply, as pointed out by the Rt Hon David Willetts MP in "Eight Great Technologies". It will also facilitate the increased use of intermittent renewable energies (such as wind, wave and tidal) on the grid to meet binding emission targets (for example, 80% CO2 reduction by 2050) and thus enable the faster transition to a low carbon society. This calls for low cost and sustainable energy storage technologies. Na ion batteries (NIBs) have recently attracted increasing interest worldwide, because of the natural abundance, wide availability and low cost of Na resources. They may be more economically viable than lithium-based batteries in the context of grid storage and can support the UK's and even the world-wide demand for electricity storage. The development of NIBs has, however, been very slow in the UK, compared to other competitors such as USA, Japan and China. This project aims to make advancements in NIBs with a focus on anode materials.

This project proposes the use of low cost and aboundant nanoporous carbons materials (particularly biomass derived carbon aerogels) as anode materials in NIBs. This proposal details a necessary step by providing a design tool for selection and optimisation of nanoporous carbons in this application. The hypothesis of the research is that computational models can be used to design desirable porous carbons for NIBs. The model development will be supported and validated by experimental activities including characterisation of real nanoporous carbons, assembly and testing of NIB cells.

Molecular models will be developed at two levels - a single pore model and a more complicated virtual porous carbon model. Hetereatoms (such as H, O, B, N, P, S) in the forms of doped atoms in the carbon lattices, and funcational groups, will be introduced, for the first time, to reflect the real atomic structures of porous carbons. Molecular simulations will be performed on the models to reveal Na ion intercalation mechanism in nanoporous carbons and the effects of pore sizes and presence of heteroatoms on the adsorption, diffusion and charge transfer processes. Desirable characteristics of porous carbons will be generated. These desirable charateristics will be used to guide the fabrication and optimisation of real nanoporous carbons.

This project is underpinned by a fully funded PhD studentship at Surrey, which will enable the prediction and the understanding from molecular simulations to be directly translated into real applications. Biomass derived nanoporous carbon aerogels, produced at Queen Mary University of London (UK), will be used to manufacture NIB cells at University of Surrey for electrochemical performance testing. Nanoporous carbons of other origin will be produced at CIC-Energigune (Spain) and used in battery cell manufacturing and testing. The project is also strongly supported by Johnson Matthey on materials characterization, battery testing, and advice on prototype opportunities.

This project is the natural result of the PI's expertise in molecular simulation, nanoporous carbon materials and electrode design for electrochemical devices. The framework of the proposed work will be underpinned by extensive energy materials characterisation expertise and infrastructure, as well as extensive expertise and facilities in battery manufacturing and testing at Surrey.

This project aims to make advancement of Na-ion battery (NIB) technology. The project will lead multidisciplinary research to enable tuning of materials for improved performance and faster development of NIB technology.

The successful delivery of this project will lead to production of prototype NIB cells and future commercialisation of this technology, which provides a cheaper, cleaner, safer and sustainable energy storage solution. Moreover, molecular models of nanoporous carbons from this research could facilitate the design of carbons in supercapacitors, Li-air batteries and low-temperature fuel cells, with important impact on those industries.

Commercial beneficiaries of the research (wealth generation in 10 - 25 years) will be companies in the UK and worldwide in, or part of the supply chain for, NIB technology. More specifically, in the 5 - 15 year window, UK industry will directly benefit if the outcomes of the research lead to more developed and focussed academic-industry collaborations (Technology Strategy Board / Knowledge Transfer Partnerships). The potential IP that could be generated in the area of NIB technology for energy storage will yield opportunities for spin-out companies, providing employment opportunities and adding value to the UK economy.

Societal beneficiaries will include, for example:
- greater energy storage capacity in the UK and thus huge saving in energy bills for the public;
- large-scale employment of renewable energies (in the UK, particularly wind, wave and tidal energy) and thus the transition to a low carbon society;
- enhancement of UK's energy security and environmental sustainability.

In short-term (1-3 years), this project will provide highly skilled researchers who will have developed multidisciplinary skills and will have experienced a broad range of technological fields that are important for R&D programmes required for market innovation for NIB technology and beyond.

The PI will benefit several new collaborations with Johnson Matthey, Queen Mary University of London and CIC-Energigune (Spain), above established collaborations associated with her current research programmes. The UK-based and international partners are committed to supporting aspects of this project within their own research capacity. Further collaborations with leading groups and the development of multidisciplinary research projects will be fostered during this project.