Neutron Compton Scattering For Functional Energy Materials

The aim of this proposed research is to exploit new developments in neutron scattering at eV energies, to investigate the quantum behaviour of protons and other light atoms in a range of systems of fundamental scientific and technological interest. For example; the study of the lithium momentum distribution in materials used in battery technology, the momentum distribution of protons and lithium in lithium-ammonia solutions/metallic solid, measurements on ammonia related compounds which are potential hydrogen storage materials and the determination of the role of oxygen atoms in high Tc superconducting materials.

Strong links have been forged with the Rutherford Appleton Laboratory, the groups of Car and Parinello and with the groups of Andreani and Colognesi in Italy. Results from this research will be used to further develop and benchmark state of the art calculations, considering the complexity of both measuring and calculating quantum effects in momentum distribution. The project will also further develop an experimental technique in which the UK currently has a world lead. This will be to the benefit of a wide range of scientific disciplines.

The UK currently has the world lead in research centred around the swiftly growing technique of neutron Compton scattering, with the ISIS pulsed neutron source (Chilton, UK) having the only instrument currently able to make such measurements. Recently, our group has shown that there is application of this technique outside of studying only hydrogen and helium, by extending the technique to heavier masses. This would make NCS the ONLY neutron technique able to routinely examine and isolate multiple masses in a system, including lithium (the most important nucleus for battery materials), oxygen (critical for high temperature superconductors) and nitrogen (and by extension ammonia, NH3, perhaps the most important industrial compound).

Any such development will open this field to enable application beyond condensed matter physics, into the realms of applied chemistry and materials research. Technologically, a development of NCS would ensure that the UK remains the world-leader in high energy neutron scattering even after the U.S.A. have built the new spectrometer, for which permission has been granted at the Oak Ridge national laboratory.

As part of this proposal, colse ties are being forged with theoretical and applied researchers in Italy and the U.S.A., ensuring that there is an exchange in skills between these two countries and the U.K., principally via the PDRA position funded by this proposal.

In order to develop NCS as a technique, trial systems must be chosen whereby measurements can be used to benchmark and influence both calculation and data analysis, even instrumental design and setup. To do this, we have chosen 4 appropriate systems, but also ensured that these systems are not chosen on this merit alone. Instead, we have confined our research to systems of great environmental and future energy importance. Our group has extensive background in the field of renewable energy research, optimisation and development, as witnessed in the other documents of this proposal. We will thus be able to develop not only NCS as a technique, but also better understand these energy-material systems at the most fundamental, quantum level. NCS is able to offer insights into the quantum behaviour of nuclei that is not accessible by ANY other spectroscopic technique.

The systems studied are of interest not only to academia, but also to industry, where our group has active collaborations on synthetic projects with Toyota, Johnson Matthey and Illica. The project detailed in this proposal will act as proof of concept for the application of NCS as an important spectroscopic tool (and as an extension of now standard neutron techniques) for utilisation by industry.