Enhancing Performance in Polyanionic Cathode Materials

The increasing threat posed by climate change has made energy storage more important than ever before. Lithium-ion batteries (LIB) have revolutionised portable electronics and have growing impact in electric vehicles. This success is due to their high energy densities which permit small light batteries to power increasingly small and complicated electronic devices. However, new generations of battery materials are required which combine high energy and power densities with low cost and high safety, for applications such as electric vehicles or static energy storage. The need to reduce CO2 emissions prioritises the use of renewable energy sources as opposed to the burning of fossil fuels. The intermittent nature of these renewable energy sources and the need to match supply with demand requires the storage of excess energy generated at peak production so that it may be released at times of peak demand. Electrochemical energy storage represents one of the more attractive solutions to this challenge. Polyoxyanion compounds are receiving considerable interest as alternative cathodes to conventional oxides. The strong binding of the oxygen in polyoxyanions enhances stability and thus safety, compared with layered transition metal oxides and raises the voltage via the inductive effect. The aim of this work is to investigate new polyanion systems, particularly oxalates, including the incorporation of highly electronegative fluorine which is beneficial for improving the electrochemical performance and raising the voltage.
In a particularly exciting development, our preliminary studies indicate that in addition to conventional transition metal redox activity, the oxalate group itself may show redox behaviour.
By employing a combination of experimental and computational techniques we will be able to obtain a fuller understanding of these materials and develop them towards possible application.
In order to achieve this we have assembled a strong team of collaborators. These include academic partners for both computational (DFT) and experimental (Mossbauer and X-ray absorption spectroscopy) studies, together with industrial support from Faradion and Johnson Matthey.

Our approach will maximise the opportunity to combine transition metal and oxalate redox and thereby obtain higher capacities, beyond the conventional metal-only redox activity.

The scope of our proposal is to understand the fundamental science behind development of a novel range of materials for use as prospective cathodes in solid state (Li or Na) batteries.
This is entirely within the context of the EPSRC portfolio and aligns with the challenge theme "Energy Storage" - targetted as a 'GROW' area.The proposal also relates strongly to a number of areas within the EPSRC Physical Sciences Portfolio: Energy Materials and their Application, Electrochemical Science, Condensed Matter, Functional Ceramics, Structure.

Academic impact:
In addition to the benefits to the academic community,to which we will disseminate via high-profile publications and conferences, we will also work with the Energy Storage hub to link to key activities in this area such as the Supergen Energy Storage Grand Challenge project led by Imperial (EP/K002252/1) and the Energy Storage Hub (EP/L019469/1). We will also engage with the STFC Global Challenge Network in Battery Science and Technology, including presenting at their meetings. This may generate new research opportunities and outputs by sharing research findings thus enhancing academic impact. Although our proposed work lies outside the four fast-start projects recently announced as part of the Faraday Institute, the results we report as a result of this funding should feed directly into future projects associated with the FI initiative.

Commercial & Societal impact:
Global warming and finite fossil fuel resources together provide one of the greatest societal challenges of the 21st century. If we are to continue technological developments whilst safeguarding the planet we must deliver advances in energy generation and storage.
The UK has a target of 15% of its energy consumption to come from renewable sources by 2020 (2009 Renewable Energy Directive), whilst the Scottish Government aims to produce the equivalent of 100% of electricity requirements from renewable sources by 2020. Addressing this challenge requires innovative approaches to the generation and storage of electrical energy and careful nurturing of the translation of this research to industrial development.
All of the research work undertaken in the course of this project would be attractive to the broader public interest in science. As such the results of this research will be made available on the University of St Andrews webpage in a form suitable for public dissemination, and press releases will also be also used to maximise the impact on the general public. We have direct links (and letters of support) to two companies engaged in battery development (Johnson Matthey and Faradion). Relevant discussions will take place during the project and guidance will be sought. We will make use of the commercialisation offices at St Andrews and may seek IP protection through e.g. patents and licensing (ARA holds a patent (US Patent 6214493) on cathode materials). We will consider various options for further commercial exploitation and development of significant findings e.g. through partnership with potential industrial concerns.

Training of highly skilled scientists:
The project will provide comprehensive training of a post-doctoral fellow in a range of both research-specific state-of-the-art characterisation techniques and a range of transferrable skills. The breadth of training in scientific methods, critical thinking, and time-management will prepare the early-career scientist equally well for a leading role in either an academic or industrial position. The supply of such highly-trained individuals is an important commodity for the UK economy.