New Li-S Batteries Far Exceed Li-Ion Capacity

Article By : M. Di Paolo Emilio

Researchers at Monash University were able to design a new lithium-sulfur (Li-S) battery that is much more efficient than current lithium-ion products.

A battery with five times the capacity of lithium-ion batteries and low environmental pick-up could lead to the development of drastically cheaper electric cars and large-scale storage of mains power. The battery, based on lithium and sulfur (Li-S) is capable of maintaining 99% efficiency for more than 200 charge and discharge cycles; if used to power a smartphone, it would be able to keep it running for five days (Figure 1).

The new battery was developed by Mahdokht Shaibani, a researcher in the mechanical engineering and aerospace department at Monash University in Melbourne, Australia, and her colleagues.

The researchers have filed a patent (PCT / AU 2019/051239) for their manufacturing process, and the prototype cells have been successfully manufactured by German partners including Fraunhofer Institute for Material and Beam Technology. Scientists believe that this development could transform the way phones, cars, computers and solar networks will be produced in the future. The study was published in Science Advances.

The research group includes Shaibani, and her team at Monash University; along with colleagues from CSIRO, the University of Liège, Fraunhofer, and Beam Technology.

“The design and implementation of Li-S batteries could revolutionize the automotive market,” said Mainak Majumder, one of the authors and a professor at Monash.


Figure 1: Associate Professor Matthew Hill, Dr. Mahdokht Shaibani, and Professor Mainak Majumder [credit: Monash University]
Figure 1: Associate Professor Matthew Hill, Dr. Mahdokht Shaibani, and Professor Mainak Majumder [credit: Monash University]


When it comes to batteries, everyone is always looking for new solutions that offer longer life and sustainability. Researchers are always working on batteries that can charge more and last longer.

To date, the weak point of lithium-sulfur batteries is due to the high capacity of the sulfur electrode, which is so large that it breaks with the normal battery charge and discharge cycles. The sulfur electrode expands and contracts during cycles, and the volume of the electrode changes by about 78%.

Higher energy performance is rapidly attenuated when the sulfur electrode is charged to the required levels, 5 to 10 mg cm-2, due to the substantial change in lithiation/delithiation volume and the resulting stresses. The researchers provided more space for the sulfur particles at a chemical level, using a smaller amount of polymeric material that serves to hold the particles together in their electrode, thus creating more spaced structures between the sulfur particles. With the same materials as lithium-ion batteries, the researchers reconfigured the design of the sulfur cathodes so that they could withstand higher stress loads without a drop in overall capacity or performance.

This lithium-sulfur battery could dramatically reduce the cost of batteries because sulfur is an abundant and extremely economical chemical element. However, there may be ethical problems similar to those associated with the production of lithium-ion batteries. The main problem regarding electric mobility is related to the process of extracting the raw materials necessary for the production of batteries. Many studies are also focusing on the exploitation of cheaper components with a lower environmental impact, such as sulfur.

According to scientists, by 2050, the number of electric vehicles on the road will reach 965 million, and the storage capacity of batteries will have to rise to 12,380 GWh, while that of photovoltaic systems will have to exceed 7,100 GW. In the coming years, the demand for metals will grow considerably.

Batteries are among the key technologies to bring the European energy supply system out of hydrocarbons in the coming years, both in terms of transport and electricity. Sulfur is much easier to find and cheaper, not least because it is also a waste product of oil processing. In the near future, we will need new generations of high-performance, reliable, safe, sustainable, and affordable batteries.

Energy storage systems will play an increasingly crucial role in the complete decarbonization of the electrical and thermal systems. The transition from fossil fuels to renewable energy cannot fail to include the development of advanced energy storage technologies, such as storage systems and batteries.

Compared to traditional lithium-ion (Li-ion) batteries, the new technology for energy storage involves the use of sulfur, which is a very economical material, with higher overload tolerance, lower toxicity, and lower weight than traditional lithium ions.

Taking advantage of the electrochemical reactions of Li-S batteries could lead to exciting new developments in various fields of application. Other researchers have found that wrapping the sulfur-carbon energy storage in a thin, flexible graphene sheet accelerates the transport of electrons and ions to improve performance and electrical conductivity. By wrapping the sulfur-carbon unit in a graphene sheet, you can achieve a longer battery life, better cycle stability, and higher efficiency.

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