A high-performance lithiated silicon–sulfur battery with pomegranate-structured electrodes

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 the lifespan of lithiated Si–S batteries. To simultaneously address both the issues, this work report on a new lithiated 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. In the meantime, 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. As a result, the newly developed lithiated 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).