Defects by Design; Understanding and Controlling Defect Processes in Advanced Energy Materials

There is an urgent demand for next-generation energy materials which can provide the necessary cost decreases and performance boosts to create a sustainable green economy. Using a high-throughput computational materials modelling strategy, we aim to enhance the performance of relevant energy materials, namely photovoltaic solar cells, batteries and thermoelectric, via the controlled implementation of crystalline defects.
When the body creates billions of genetic code in DNA, there are inevitable imperfections termed genetic mutations. Likewise, there are similar inevitable imperfections in every solid-state material which can significantly enhance or degrade device performance, such as solar cell efficiency, battery capacity and battery lifetime. However, it is challenging to identify the specific defects which improve performance or trigger degradation and efficiency reduction. Modern defect theory provides a powerful tool for understanding and controlling defects in crystals (predicting concentrations and transport rates) and in interpreting experimental probes of defect processes, including activation energies for diffusion, and electronic/vibrational/spin signatures.

In this project, we will develop a novel software infrastructure for the characterisation of defects in crystalline solids and predicting signatures for direct comparison between modelling and experiment. Specifically, the computational approach of hybrid Density Functional Theory (DFT) will be implemented to investigate the defect chemistry of relevant energy materials, through the calculation of defect formation energies, characterisation of defect core levels and identification of stable oxidation states. The insights gained from this work will be applied to the cutting edge of solid-state energy material research and development, optimising energy device performance and cost by providing design strategies to overcome current limitations. Predictions will be validated with experimental partners at Cambridge, Imperial College London and UCL. Moreover, this research will provide a novel framework for in-depth high-throughput investigations of defects in solid-state materials, which will prove a valuable research community tool for defect design applicable to other materials systems.

This project is most relevant to the EPSRC research theme of 'Energy', specifically the research areas of 'Materials for Energy Applications', 'Energy Storage' (both of which are classified as target areas for growth in EPSRC investment), in addition to the area 'Condensed Matter: Electronic Structure' in the 'Physical Sciences' theme.

The production and processing of materials accounts for 15% of UK GDP and generates exports valued at £50bn annually, with UK materials related industries having a turnover of £197bn/year. It is, therefore, clear that the success of the UK economy is linked to the success of high value materials manufacturing, spanning a broad range of industrial sectors. In order to remain competitive and innovate in these sectors it is necessary to understand fundamental properties and critical processes at a range of length scales and dynamically and link these to the materials' performance. It is in this underpinning space that the CDT-ACM fits.

The impact of the CDT will be wide reaching, encompassing all organisations who research, manufacture or use advanced materials in sectors ranging from energy and transport to healthcare and the environment. Industry will benefit from the supply of highly skilled research scientists and engineers with the training necessary to advance materials development in all of these crucial areas. UK and international research facilities (Diamond, ISIS, ILL etc.) will benefit greatly from the supply of trained researchers who have both in-depth knowledge of advanced characterisation techniques and a broad understanding of materials and their properties. UK academia will benefit from a pipeline of researchers trained in state-of the art techniques in world leading research groups, who will be in prime positions to win prestigious fellowships and lectureships. From a broader perspective, society in general will benefit from the range of planned outreach activities, such as the Mary Rose Trust, the Royal Society Summer Exhibition and visits to schools. These activities will both inform the general public and inspire the next generation of scientists.

The cohort based training offered by the CDT-ACM will provide the next generation of research scientists and engineers who will pioneer new research techniques, design new multi-instrument workflows and advance our knowledge in diverse fields. We will produce 70 highly qualified and skilled researchers who will support the development of new technologies, in for instance the field of electric vehicles, an area of direct relevance to the UK industrial impact strategy.
In summary, the CDT will address a skills gap that has arisen through the rapid development of new characterisation techniques; therefore, it will have a positive impact on industry, research facilities and academia and, consequently, wider society by consolidating and strengthening UK leadership in this field.