Lithium Rich Transition Metal Oxides as High Capacity and High Voltage Li-ion Battery Cathodes – synthesis and characterisation

Supervisors: V. R. Dhanak and L. J. Hardwick

The project - The increasing energy consumption of modern societies has created a considerable demand for better approaches to not only the production and management of energy, but also its storage. Due to their high energy density and good specific energies lithium-ion batteries are attractive candidates for use in many applications such as portable devices, though there is considerable impetus for further improvement.

One potentially attractive family of cathode materials are layered lithium-manganese rich, mixed metal oxides (LMR-MMO materials), of the form xLi₂MnO₃:(1-x)LiMO₂ (where 0 < x < 1, and M represents transition metals such as cobalt, manganese and/or nickel).Their high capacities (at low cycling rates in excess of 220 mAh g^-1 at room temperature and 300 mAh g^-1 at 60^◦C) have generated considerable interest. However, there are still significant challenges to overcome - chiefly the material exhibits power loss due to voltage fade on cycling. Furthermore, whilst properties such as capacity and cyclability are self-evidently of considerable importance, many applications require rapid access to stored energy and fast recharge times. Consequently, developing materials capable of operating at high rates is potentially quite significant.

The project will also involve the study of Mo and Cr based Li-Rich cation-disordered oxides materials that have recently been reported within Science that offer superior capacities over conventional Li-ion cathodes. This discovery has opened up the field to the possibility of non-stoichiometric oxides that have promising electrochemical behaviour.

Surface reactivity plays a major role in the capacity and cycle life of these materials. Understanding the surface physics and chemistry is critical in developing synthetic methods that permit greater stability within these classes of materials to permit their future commercialisation. There is major world-wide interest in this family of materials as they are seen as the future cathodes for Li-ion.

The prospective student will synthesise these advanced materials and use photoemission techniques to characterise them. In particular, X-ray Photoelectron Spectroscopy is a crucial technique that will be used in achieving step-change advances in material development process and to understand the surface physics and chemistry, and ageing of battery materials.

For more details contact Vin Dhanak (vin@liverpool.ac.uk)

To apply, please complete the online application form that is available at http://www.liv.ac.uk/physics/postgraduate/postgraduate-research/physics-mphil-phd/applying/