Researchers in Hong Kong have developed a new lithiated silicon-sulfur (Si–S) full battery by developing pomegranate-structured hosts for both the anode and cathode. The pomegranate-like sulfur host with titanium nitride-carbon dual-layer hollow nanospheres (Pome-TiN@C) not only effectively suppresses the polysulfides diffusion by multiple layers of chemical and physical barriers, but also facilitates their conversion reactions.

A paper on their work is published in the Journal of Power Sources.

Lithiated silicon-sulfur (Si–S) batteries are promising next-generation energy storage systems because of their high theoretical energy density, low cost, and high safety. However, the unstable solid-electrolyte interphase (SEI) on the Si anode and its side reactions with highly soluble polysulfides limit their lifespan.

With the new structures, Si nanoparticles are encapsulated in an integrated pomegranate-like carbon framework (Pome-Si@C), which accommodates the large volume variation of Si and guides the formation of stable SEI to prevent undesired side reactions.

Zhang et al.

As a result, the Si–S full battery achieves a high reversible capacity (940 mAh g⁻¹ at 300 mA g⁻¹); a superior rate capability (537 mAh g⁻¹ at 2 A g⁻¹), and long cycle life (508 mAh g⁻¹ remains after 300 cycles at 500 mA g⁻¹).

Resources

• Leicheng Zhang, Chen Zhao, Qinping Jian, Maochun Wu, Tianshou Zhao (2021) “A high-performance lithiated silicon–sulfur battery with pomegranate-structured electrodes,” Journal of Power Sources, Volume 506 doi: 10.1016/j.jpowsour.2021.230174