Powering new energy designs

Australia has the highest average solar radiation per square metre in the world, although solar power is only generated during the daytime and varies according to weather conditions. Similarly, wind resources are concentrated in certain regions and wind turbines can only generate electricity when the wind blows. This intrinsic intermittency and instability make it difficult to be completely fossil fuel free at this point.

While we can’t control the weather, reducing the amount of energy we use means we won’t need such a big supply. Also building more facilities, and developing new ways to store and convert collected clean energy and smoothly integrating it with existing electrical grids, can help meet our demands too.

It is well accepted that electrical energy storage can not only improve the reliability and overall use of the entire electrical grid but can also effectively provide balancing services for grids by absorbing electricity whenever there is too much generation (normally off-peak time) and by injecting electrical energy in to the grids when the generation in insufficient (often during peak times).

Late in 2019, Distinguished Professor Zaiping Guo and her team were one of the 18 Discovery projects from UOW to receive funding from the Australian Research Council. The overall aim of their project aims to advance energy storage technology by developing high-energy aqueous rechargeable zinc batteries with low cost, high safety, high energy density and long cycle life for grid scale energy storage.

D/Prof Guo is a well-known expert in material design and electrochemistry. Over the last 20 years she has worked within the area of energy storage, including lithium-ion batteries, lithium-sulphur batteries, sodium ion batteries, potassium ion batteries, supercapacitors and hydrogen storage materials. Guo was also among the recipients of the 2018 and 2019 Highly Cited Researcher awards.

For this project she is joined by Dr Mao from UOW, who has extensive experience in hydrogen storage materials, electrode materials, and various new batteries materials. Also in the team is Professor Chunsheng Wang from University of Maryland, who is a world- leading researcher on aqueous electrochemistry and batteries. His scientific breakthrough in the invention of water-in-salt electrolytes enables high-voltage aqueous lithium-ion chemistries (Science, 2015), Zn-air batteries (Nature Materials, 2018) and high-energy cathode (Nature, 2019), has opened an entirely new area of aqueous electrochemistry and batteries that never existed before.

One may ask why not work on optimising existing rechargeable battery options such as Lithium-ion batteries? While Lithium-ion batteries dominate the present electrochemical energy storage landscape, widely used in portable electronics and considered for electric vehicles, as well as large-scale energy storage systems due to their high energy density. However, the increasing concerns about cost, safety, the limited lithium resources as well as environmental impact motivate the search of alternative battery systems.

In this regard, rechargeable aqueous batteries using water-based electrolytes with good safety, easy assembly, lower cost, environmental benignity, and higher ionic conductivity compared with the case of organic electrolytes, are promising alternatives for grid-scale electrochemical energy storage.

In particular, aqueous zinc-ion batteries (ZIBs) outperform others owing to the properties of Zn anodes, including low-cost stemming from high abundance and large-scale production, nontoxicity, high capacity, considerable electrochemical stability in water due to a high over potential for hydrogen evolution. Moreover, ZIBs operate through a multiple-electron transfer, rendering higher storage capacity compared to Li- or Na-ion batteries.

The proposed zinc battery system will advance storage technology and implement clean energy into a smart grid in an efficient, safe and sustainable way. It will also generate new fundamental on designing high performance electrode materials and enhance our understanding of the charge storage and kinetics in zinc batteries, which will provide guidance for developing alternative energy storage devices. The project will also assist in training students and young scientists in this emerging area, and support Australia’s access to new high-technology markets. This high powered research collaboration aims to enhance the international competitiveness of Australia in the energy storage field, as well as reducing our dependence on fossil fuels, and facilitate a more sustainable Australia.

• DISTINGUISHED PROFESSOR ZAIPING GOU: Take a look at Zaiping's Scholars profile to find out more and link to her papers
• THE INSTITUTE FOR SUPERCONDUCTING AND ELECTRONIC MATERIALS: ISEM is a world-class collaborative team conducting research in superconducting and electronic materials science and technology. Learn more.