Battery Technology
The global energy demand is increasing and finding new sustainable energy alternatives to fossil fuels is now critically important. As non-continuous sources such as solar and wind power play a larger role in our energy production, the development of effective and sustainable energy storage systems is imperative. Our group is developing novel and sustainable carbon materials to be used in key energy storage technologies such as Na-ion batteries, Na-metal batteries, Li-S batteries and mixed-ion systems.
Material preparation
We produce hard carbons for ion storage from two main feedstocks: biomass-derived products and plastic waste. By subjecting either precursor to autogenic pressures and/or solvents (e.g. water, water/ethanol, CO2), generated in tightly closed reactors at mild temperatures (200-500 C), we obtain pre-carbonised materials that can be then further graphitised at higher temperatures.
Biomass-derived carbons (HTC) Plastic waste-derived carbons
Battery basics
A typical battery consists of two electrodes (cathode and anode), separated by an electrolyte which can conduct ions but not electrons.
On charging, ions travel from the cathode to the anode, and the electrons simultaneously pass around the external circuit, creating a flow of current. The reverse occurs during cell discharge.
Na-ion batteries
Sodium ion batteries are a diversification alternative to lithium batteries due to their similar chemistries, the abundance of sodium ion battery materials and its safety.
Fast degradation and reduced long term cycle life however hinder commercialization of sodium ion batteries. This is partly due to reactions occurring at the electrode-electrolyte interface and the structural degradation of the cathode. The capacity of the hard carbon anodes also needs to be improved for successful scale up of sodium ion batteries.
In the Titirici group, we make efforts towards this by:
Developing hard carbon thick electrodes (Yichen)
Operando studies through correlated electron microscopy and synchrotron techniques (Conor)
Upscaling hard carbon anode materials for commercialization (Johny)
Life cycle assessment of the hard carbon production process (Mengnan)
Recycling sodium ion battery electrodes (Xiaochu)
Dual-ion batteries
Dual-ion batteries (DIBs) are emerging batteries with comparable performance to lithium-ion batteries.
The mechanism of DIBs is different from lithium-ion batteries -working by anions and cations de-intercalation into separated electrodes, which shortens the ion diffusion path and enable fast charging.
DIBs can achieve an all-carbon configuration, replacing the expensive layered metal-oxide cathode with graphite.
DIBs are promising especially in terms of EVs and large-scale infrastructures for energy storage.
Li-S batteries
Li-S batteries exhibit a number of advantages over current state-of-the-art Li-ion battery chemistries, including increased specific energy densities and reduced environmental impact.
However, their commercialisation is hindered by a number of issues including safety challenges and longevity of cells.
In the Titirici group we work on improving the performance of both the lithium metal anode and the sulphur cathode by:
