Designing dual-confined nanoreactor with built-in small-sized platinum nanoparticles for advanced Li-SeS2 batteries

Highlights: • Constructing dual-confined catalytic nanoreactor as cathode host for Li-SeS₂ batteries. • Realizing efficient anchoring and fast conversion of polysulfides/polyselenides. • The cell exhibits excellent electrochemical performance. -- Abstract: A dual-confined nanostructured reactor, featured with the small-sized platinum nanoparticles embedded in dendritic mesoporous silica nanospheres with a hierarchical porous graphene-like carbon protection shell, is designed and synthesized as an efficient SeS₂ host for high-performance lithium-selenium/sulfur batteries. The rationally designed host framework, which combines the merits of strong chemical interaction effect, abundant catalytic active sites, and excellent conducting network, can realize efficient anchoring and fast conversion of lithium polysulfides/polyselenides during the electrochemical processes. Thus, this SeS₂-based cathode shows a high initial capacity of 1013 mAh g⁻¹ at 0.2 A g⁻¹ and an outstanding cycling stability, with a capacity of 426 mAh g⁻¹ over 500 cycles at 2 A g⁻¹, corresponding to a low capacity decay of 0.07% per cycle. This study demonstrates a novel and efficient approach to overcome the hurdles of current lithium-sulfur systems for stable rechargeable batteries.