Advancing the potential of lithium-sulfur batteries

Researchers from UNSW’s Particles and Catalysis Research Laboratory are working hard to close the technological gap that is preventing the wholesale commercialisation of Li-S batteries.

Jenny Sun, PhD candidate, UNSW Particles and Catalysis Research Laboratory

High density energy storage is the focus of hundreds of lithium-based battery researchers around the world. At UNSW, this piece of the puzzle is being pored over by PhD candidate Jenny Sun from the Particles and Catalysis Research Laboratory (PARTCAT), within the School of Chemical Engineering.

Sun is involved in a project to develop the next generation of lithium-sulfur rechargeable batteries (Li-S battery) which will, she believes, improve on the energy density, lifetime and safety of other lithium-based batteries. “Specifically, I’m working on an Li-S pouch cell which we think will have considerably higher energy density than commercial Li-ion batteries,” Sun says.

According to Sun, despite the enormous progress globally at lab stage, industry has not yet commenced commercialisation of Li-S batteries due to the technological gaps from lab to market. “We have built a prototype Li-S pouch cell and are working now to assess and improve the usability of the battery and develop mature and practical technology for industrial R&D,” she continues.

To do this, Sun and her PhD supervisors, Dr Da-Wei Wang and Scientia Professor Rose Amal, are simulating the industrial production process at lab scale and strictly keeping the fabrication parameters at the same level as in industry. “We are trying to solve the common problem of performance downgrade from lab to industry by innovative design and optimisation of battery components, which are also adaptable with the industrial processing,” says Wang. “The key issue of Li–S battery is the low electrical conductivity of the sulfur cathode resulting in the need for extra mass for a conducting agent. Our current research focus is to find highly conductive and highly loaded cathodes.”

Currently, lithium-ion batteries are prolific in our mobile phones, sensors and cars but they have limitations. Li-S batteries are attractive because sulfur is cheap, safe and also has large specific capacity (about 1,675 mAh/g). Pouch cells are attractive because they are very simple, flexible, lightweight and can achieve a very high percent packaging efficiency.

Li-S battery pouch

Sun says her next step will be to focus on modifying the electrodes and separating the different components in the battery to achieve cheaper and better electrochemical performance. “It’s great to be working towards solving one of the most important problems related to electrical devices: replacing lithium-ion batteries with high energy density and more stable Li-S batteries,” she says.

“This research is particularly interesting, because I’m not only focusing on the research but also its application. I’m trying to link it to industry. My main aim with the Li-S pouch cell is to confirm that it is viable for industry use and we will soon be seeking opportunities to work with industry to collaborate and improve the technology further,” says Sun.

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