DOCTORAL CANDIDATE
Widi Kurniawati

SUPERVISORS
Dr. Laurence Croguennec
Dr. Jacob Olchowka
Prof. Jenny Pringle

Electrochemical energy storage, batteries, inorganic electrode and organic electrolyte materials for energy, material sciences

Lithium ion batteries have become an essential part of our everyday lives and their demand continues to increase, for use in a wide range of applications from transport to portable electronics to stationary storage for renewables. Advancement of these applications requires improving the energy density and safety of lithium batteries, which can be achieved by a number of different strategies. Lithium metal can be used as the anode, but successfully using this reactive metal requires careful selection of the electrolyte and understanding and controlling the properties of the electrode/electrolyte interface. High voltage cathodes, such as those based on manganese-rich compounds, are under development to improve the energy density of lithium-ion batteries, and these require combination with high electrochemical stability electrolytes. Finally, the use of solid-state electrolytes instead of liquid electrolytes can be very advantageous for safety, reducing leakage and flammability and allowing use of more reactive electrodes. However, the challenge is to maintain good contact and ion conduction at the electrolyte/electrode interface. This project will utilise a range of materials and analysis techniques to investigate these approaches, to develop higher energy density lithium batteries.

Spinel type manganese-rich compounds, bare or modified at the surface, will be used as the positive electrode. These electrodes will be used in combination with novel quasi-solid-state electrolytes based on organic ionic plastic crystals (OIPCs). OIPCs are composed entirely of ions, with a wide range of possible chemical, thermal and transport properties depending on the type of ions used. They can be used to form quasi-solid-state electrolyte by mixing with lithium salts; these soft mechanical properties are advantageous for achieving good wettability with the electrode and maintaining good contact with cycling. However, there is much to be understood about the compatibility of OIPCs with different cathode materials and how this is affected by the nature of the two materials and by cycling. This will be investigated by studying the interfacial reactions with different electrolytes and electrodes, upon cell cycling under a range of different operating conditions. This understanding will be important for realizing the development of safer, more stable high energy density Li ion batteries.Furthermore, exploration towards the sodium technologies will also be carried out, synthesis of the materials and evaluation of the interface stability with the potential OIPCs will also be focus on this study.