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Peter Bruce

Professor Peter G Bruce FRS
Wolfson Chair

Department of Materials
University of Oxford
Parks Road
Oxford OX1 3PH
UK

Tel: +44 1865 612760 (Room 271.10.09)
Tel: +44 1865 273777 (reception)
Fax: +44 1865 273789 (general fax)

Research Group website

Summary of Interests

My primary research interests are in the fields of solid state chemistry and electrochemistry; particularly solid state ionics, which embraces ionically conducting solids and intercalation compounds. I am interested in the fundamental science of ionically conducting solids (ceramic and polymeric materials) and intercalation compounds, in the synthesis of new materials with new properties or combinations of properties, in understanding these properties and in exploring their applications in new devices, especially energy storage devices such as rechargeable lithium batteries. Although ionically conducting solids represent the starting point for much of our research, we have extended our interests well beyond the confines of this subject alone.

Projects Available

Three projects on the materials chemistry and electrochemistry of batteries: lithium-air, all solid state lithium and sodium-ion batteries
Prof Peter G Bruce (Wolfson Chair in Materials, Departments of Materials and Chemistry)

1. The materials chemistry and electrochemistry of the lithium-air battery

Energy storage represents one of the major scientific challenges of our time. Pioneering work in Oxford in the 1980s led to the introduction of the lithium-ion battery and the subsequent portable electronics revolution (iPad, mobile phone).

Theoretically the Li-air battery can store more energy than any other device, as such it could revolutionise energy storage. The challenge is to understand the electrochemistry and materials chemistry of the Li-air battery and by advancing the science unlock the door to a practical device. The Li-air battery consists of a lithium metal negative electrode and a porous positive electrode, separated by an organic electrolyte. On discharge, at the positive electrode, O2 is reduced to O22- forming solid Li2O2, which is oxidised on subsequent charging. It is the organic analogue of the oxygen reduction/oxygen evolution reaction in aqueous electrochemistry. The project will involve understanding the electrochemistry of O2 reduction in Li+ containing organic electrolytes to form Li2O2 and its reversal on charging. The use for redox mediators to facilitate the O2 reduction and evolution. The exploration of new electrolyte solutions and their influence of the reversibility of the reaction. The project will use a range of electrochemical, spectroscopic (Raman, FTIR, XPS, in situ mass spec.) and microscopic (AFM, TEM) methods to determine the mechanism of O2 reduction (presence and nature of intermediates e.g. superoxide) and its kinetics. Our aim is not to build devices but to understand the underlying science. We seek highly qualified, ambitious, imaginative, hard-working and self-motivated candidates. Further details may be obtained by contacting simultaneously Dr Erez Cohen at erez.cohen@materials.ox.ac.uk and Zsofia Lazar at zsofia.lazar@materials.ox.ac.uk.

2. Challenges facing all-solid-state batteries

There is increasing worldwide motivation to research and develop all-solid-state batteries in order to achieve better safety, higher energy density, as well as wider operating temperature energy storages, as compared to conventional Li-ion batteries using liquid electrolytes. All solid state batteries consist of a solid electrolyte as the main component, an intercalation cathode, e.g. LiCoO2, and an anode with the ultimate goal of implementing a lithium metal anode. The project will involve advancing the fundamental understanding from material to cell level. Synthesis of new Li+ conducting solid electrolytes and characterisation of their structural, electrochemical, electrical, and mechanical properties will be required. The work will include investigation of phenomena at solid electrode/solid electrolyte interfaces, something that is central to progressing solid state batteries but is not well understood, e.g. charge transfer, parasitic reactions, occurring at the interfaces of the electrolytes with both cathodes and anodes. Further parameters affecting the cycleability of the all-solid-state batteries will need to be identified. A range of characterisation techniques will be used, including X-ray and neutron diffraction, electron microscopy, NMR, Raman and IR spectroscopy, X-ray tomography, as well as several electrochemical techniques such as EIS and cycling. We seek highly qualified, ambitious, imaginative, hard-working and self-motivated candidates. Further details may be obtained by contacting simultaneously Dr Erez Cohen at  erez.cohen@materials.ox.ac.uk and Zsofia Lazar at zsofia.lazar@materials.ox.ac.uk.

3. The materials chemistry and electrochemistry of lithium and sodium-ion batteries

Lithium-ion batteries have revolutionised portable electronics and are now used in electric vehicles. However new generations are required for future applications in transport and storing electricity from renewable sources (wind, wave, solar). Such advances are vital to mitigating climate change. Sodium is more abundant than lithium and so attractive especially for applications on the electricity grid. Lithium and sodium ion batteries both consist of intercalation compounds as the negative and positive electrodes. The charge and discharge involves shuttling Li+ or Na+ ions between the two intercalation hosts (electrodes) across the electrolyte. In the case of Li-ion batteries currently the most common technology is still graphite (anode) and LiCoO2 (cathode). However, the development of increased energy storage in Li ion systems drives research to discover new materials. In the case of Na-ion batteries whilst the principles are analogous to that of the Li-ion battery, as yet there are no preferred candidates as electrodes, which provides excellent motivation for further work.

The project will involve synthesising and characterising a number of Na/Li containing transition metal oxides. This will utilise synthesis methods such as sol-gel, hydrothermal and solid state, characterisation will involve X-ray and Neutron diffraction, solid state NMR, XPS, FTIR, TEM and SEM. Additionally it is important to understand the processes at the interfaces between the intercalation oxides and the organic electrolyte. For such the interfacial studies FTIR, Raman, in situ mass spec and XPS will be the main techniques. We seek highly qualified, ambitious, imaginative, hard-working and self-motivated candidates. Further details may be obtained by contacting simultaneously Dr Erez Cohen at erez.cohen@materials.ox.ac.uk and Zsofia Lazar at zsofia.lazar@materials.ox.ac.uk.

Also see homepages: Peter Bruce

New approaches to the cathode-solid electrolyte interface in the manufacture of solid-state batteries
Professor P S Grant, Professor Mauro Pasta and Professor P G Bruce

To reduce climate change and local pollution the combustion engine must be replaced by an electric drivetrain supplied by safe, high energy density, high power density, and long-life rechargeable batteries. Solid-state batteries (SSBs) are attractive for this application because they use non-flammable solid-electrolytes that are inherently safe, and high energy density Li-metal anodes and high voltage cathodes that are unstable in conventional liquid electrolytes. However, SSB manufacturing is immature and unsatisfactory in some aspects, in particular there is a lack of knowledge in how to manufacture interfaces between the solid-state electrolyte and the cathode material that can withstand the expansion/contraction during battery charge/discharge (a problem that does not arise in a conventional Li ion battery where the liquid electrolyte is always in contact with electrochemically active material in the cathode). This is one of the most significant issues facing the viability of SSBs.

The project will investigate new ideas for manufacturing SSBs using variants of additive manufacture, 3D printing and templating to improve the robustness of the cathode response to long term charge/discharge cycling. Alongside manufacturing research and energy storage performance, the work will involve working with modelling researchers to understand how to design better energy storage devices from a microstructural point of view (porosity, particle size, grading, etc), and 3D microstructural characterisation of devices using 3D sectioning/reconstruction and X-ray tomography.

This Faraday Institution-funded 4-year DPhil in Materials studentship will provide full fees and maintenance for a student with home fee status (this status includes an EU student who has spent the previous three years (or more) in the UK undertaking undergraduate study).  The stipend will be at least £20,000 per year.  Candidates with EU fee status are eligible for a fees-only award, but would have to provide funding for their living costs from another source such as personal funds or a scholarship.  Information on fee status can be found at http://www.ox.ac.uk/admissions/graduate/fees-and-funding/fees-and-other-charges.

Any questions concerning the project can be addressed to Professor Patrick Grant, Mauro Pasta or Professor Peter Bruce (patrick.grant@materials.ox.ac.uk; mauro.pasta@materials.ox.ac.uk or peter.bruce@materials.ox.ac.uk).  General enquiries on how to apply can be made by e‑mail to graduate.studies@materials.ox.ac.uk.  You must complete the standard Oxford University Application for Graduate Studies.  Further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.

Also see homepages: Peter Bruce Patrick Grant Mauro Pasta

Atomic-scale characterisation of Li battery materials
Prof P D Nellist, Prof P G Bruce

Transmission electron microscopy (TEM) is now capable of imaging individual atoms in materials, and electron spectroscopy data can provide atomic-scale information about the elements present and the nature of the bonding. Oxford Materials is one of the leading departments in high-precision quantitative measurements of materials using these methods. These methods have great potential for measuring structure and local chemistry to explain the performance of Li battery materials and to guide their development. The big challenge, however, is that the materials used are very sensitive to damage due to the illuminating electron beam. The aim of this project is to make use of methods recently developed in Oxford to maximise the amount of information gained from the microscope for the minimum electron irradiation. In particular, the recently developed method of electron ptychography (somewhat related to holography) can provide very sensitive measurements of Li and O atoms with three-dimensional information available. This will allow, for example, the positions of Li and O atoms in an electrode to be determined at various stages of the charge and discharge cycle of a battery. The project is suitable for someone interested in applying state-of-the-art atomic resolution electron microscopy to an important and rapidly developing class of materials.

Also see homepages: Peter Bruce Peter Nellist

Understanding battery chemistry with in-situ electron microscopy
Dr Alex W Robertson and Prof Peter G Bruce

Lithium-ion batteries have revolutionised the way we think of energy storage, allowing for powerful devices that fit the palm of our hands, and massive battery arrays to supplement intermittent renewables. However there are fundamental limitations; the recent high profile fires that occurred in the Samsung Galaxy Note phones, and the 2013 grounding of the Boeing Dreamliner fleet, both illustrate this. The materials failures that occurred in these batteries risk becoming increasingly prevalent as we push Li-ion batteries to their maximum potential. New battery systems will be needed, such as Na-ion or Li-air, and a more fundamental understanding of the materials degradation mechanisms will be required to prevent failure.

Transmission electron microscopy (TEM) permits the characterisation of a material’s structure down to the atomic level, along with its chemical constitution by spectroscopy. TEM has been around for many years, but recent advances have seen the profile of this venerable technique rise dramatically, with a 2017 Nobel Prize awarded for its application to biological systems. Using TEM to aid the understanding of battery chemistry has been historically difficult, as most battery chemistry occurs in solution. However, recent developments now allow for liquid phases to be studied within the TEM, permitting an unprecedented insight into the processes that occur in a battery during operation. The student, working with the world-leading battery and electron microscopy communities within the Materials Department, will harness TEM to understand the fundamental chemical and materials processes that occur in batteries.

Any questions concerning the project can be addressed to Dr Alex Robertson (alex.robertson@materials.ox.ac.uk). General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk. You must complete the standard Oxford University Application for Graduate Studies. Further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.

Also see homepages: Peter Bruce Alex Robertson

Mechanical Behaviour of solid state lithium ion batteries
Professor David Armstrong, Professor Peter Bruce

Developing a solid state lithium ion battery would have a transformative impact on energy storage, particularly in the area of personal transport, especially if it can be combined with a metallic lithium anode.  This would facilitate increased distances through increased energy densities, and improved safety through the removal of the reactive liquid electrolytes. Whilst there are a large range of materials systems being studied and many different cell and battery architectures under development, deployment of these is hampered by a need for fundamental understanding of the mechanical properties of the materials.  This is of utmost importance as the anode, cathode and electrolyte are by necessity in contact in a solid state battery as the system charges and discharges stresses are developed and the microstructure evolves and eventually these limit the system lifetimes.

This project will develop a fundamental understanding of the mechanical properties of the ceramic lithium ion conductors such as  Li1.4Al0.4Ge1.6(PO4)3 (LAGP) and  Li7La3Zr2O12 (LLZO) which have been shown to be promising electrolyte materials for solid state lithium ion batteries.  While their electrochemical properties have been well studied there is comparatively little information on the mechanical properties of these materials.  This will be followed by measuring the interfacial mechanical behaviour of these materials in contact with both anode and cathode materials.  The data produced in this way will not only be useful for seeding mechanical models of cells and batteries but also allow optimisation of processing routes for producing electrolytes with improved lifetimes.

This project will use a range of nano and mico-mechanical indentation methods to study the hardness, elastic modulus, yield stress and fracture toughness of both materials.  These properties will be related to local microstructural features through the use of scanning electron microscopy (SEM), electron back scattered diffraction (EBSD) and Raman spectroscopy.  In particular a newly commissioned pico-indenter in an SEM integrated glove box will allow testing of reactive materials such as LLZO and lithium without exposure to the air. This system is globally unique and has been funded by both the Faraday Institution and Royce Institute with which this project will interact.

This project would suit a graduate with a background in materials science or engineering with a strong and demonstrable interest in working on the integration of mechanical testing, materials processing and electrochemistry. 

This EPSRC-funded 3.5 year DPhil in Materials DTP studentship will provide full fees and maintenance for a student with home fee status (this status includes an EU student who has spent the previous three years (or more) in the UK undertaking undergraduate study).  Candidates with EU fee status are eligible for a fees-only award, but normally would have to provide funding for their living costs from another source such as personal funds or a scholarship.  The stipend will be approximately £15,777 per year.  Information on fee status can be found at http://www.ox.ac.uk/admissions/graduate/fees-and-funding/fees-and-other-charges .

Any questions concerning the project can be addressed to Professor David Armstrong (david.armstrong@materials.ox.ac.uk) or Professor Peter Bruce (peter.bruce@materials.ox.ac.uk).  General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk.  You must complete the standard Oxford University Application for Graduate Studies.  Further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.

Also see homepages: David Armstrong Peter Bruce

Also see a full listing of New projects available within the Department of Materials.