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New cathode could accelerate the commercialisation of lithium-sulfur batteries

Wed, 01/06/2021 - 10:01 -- Paul Crompton

An international team of researchers has proposed a new type of cathode design concept for lithium–sulfur batteries (Li-S) that could bridge the gap between research and commercialisation of the technologyy.

The novel cathode structure showed improved performances in a pouch cell configuration under high sulfur loading and lean electrolyte operation. 

Researchers found their 1Ah-level pouch cell with only 100% lithium excess could deliver a cell specific energy of >300Wh/kg with a columbic efficiency >95% for 80 cycles.

The cathode is composed of uniformly embedded zinc sulphide (ZnS) nanoparticles and cobalt-nitrogen-carbon (Co–N–C) single-atom catalyst to form double-end binding sites inside a highly oriented macroporous host. It can effectively immobilise and catalytically convert polysulfide intermediates during cycling, thus eliminating the shuttle effect and lithium metal corrosion, say the researchers.

Scientists were led by Cheong Ying Chan, professor of Engineering and Environment, and professor Zhao Tianshou, chair professor of Mechanical and Aerospace Engineering and director of the Hong Kong University of science and Technology.

The research was published in Nature Nanotechnology under the title ‘A high-energy and long-cycling lithium–sulfur pouch cell via a macroporous catalytic cathode with double-end binding sites’. 

Professor Zhao said: “We are still in the middle of basic research in this field. However, our novel electrode design concept and the associated breakthrough in performance represent a big step towards the practical use of a next-generation battery that is even more powerful and longer-lasting than today’s lithium-ion batteries.”

The highly oriented macroporous host can uniformly accommodate the sulfur while abundant active sites are embedded inside the host to tightly absorb the polysulfide, eliminating the shuttle effect and lithium metal corrosion. 

Li–S batteries can potentially offer an energy density of more than 500 Wh/kg, which could vehicles a 600-800km driving range, the gap between laboratoryresearch and commercialisation lays in the polysulfide shuttle effect.

This causes progressive leakage of active material from the cathode and lithium corrosion, resulting in a short life cycle for the battery. Other challenges include reducing the amount of electrolyte in the battery while maintaining stable battery performance. 

Other collaborators include researchers from Argonne National Laboratory and Stanford University in the US, Xiamen University in China, and Imam Abdulrahman Bin Faisal University in Saudi Arabia.