Jing Xu

Title : Advanced Li2S@VO2 cathode for lithium-sulfur battery

Abstract:

Lithium sulfide (Li₂S) is one of the most promising cathode materials for the next-generation advanced Li-ion batteries because of its high theoretical capacity (1167 mA h g^-1) and large energy density. However, Li₂S suffers from poor rate performance and short cycle life due to its insulating nature and polysulfide shuttle during cycling. In this work, we have proposed a facile and scalable strategy for the synthesis of nanosized Li₂S particles via a solution-based method. For further application in Li–S batteries, uniform conductive VO₂ nanobelts were deposited on the Li₂S particles to obtain nano-Li₂S@VO₂. The average size of the as-prepared nano-Li₂S particles is around 100 nm, and covered by VO₂ nanobelts with a thickness of 20 nm. These nanoscale Li₂S@VO₂ particles guarantee a short diffusion distance of lithium ions and the protective layer allows fast electron transport as well as effectively constraining the migration of the soluble polysulfides. As a result, the nano-Li₂S@VO₂ cathodes show outstanding electrochemical performance with a high initial discharge capacity of 1083.5 mA h g^-1 at 0.2 C and 766.3 mA h g^-1 after 200 cycles with a low decay of 0.15% per cycle. The enhanced electrochemical performance is due to the unique architecture with enhanced electrical conductivity and better suppression effect for the polysulfide shuttle.

Audience take away:

• Get the latest technology in the synthesize of cathode materials in Li-S battery.
• Lay solid foundation for the deep understanding of VO2 applied in Li-S battery.
• This paper solves the volume expansion of Li-S battery.

Biography:

Dr Jing Xu currently is a lecturer in electrical engineering of Zhengzhou University, she got her Ph.D degree in the University of Technology Sydney, her research mainly focuses on the synthesis of novel, porous, and functional nanomaterials for lithium–sulfur battery.