Metastable marcasite NiSe2 nanodendrites on carbon fiber clothes to suppress polysulfide shuttling for high-performance lithium-sulfur batteries.

Incorporation of catalytic component is a promising strategy to promote the redox reaction kinetics and suppress the polysulfide shuttling for high-performance lithium-sulfur batteries (LSBs). In this work, metastable marcasite NiSe2 nanodendrites grown on carbon fiber cloth (m-NiSe2/CFC) are synthesized to improve chemical adsorption and electrocatalytic activity towards lithium polysulfides. The multifunctional m-NiSe2/CFC film is utilized as both the interlayer and the three-dimensional (3D) current collector in LSBs. In comparison with the stable pyrite NiSe2 nanodendrites covered CFC (p-NiSe2/CFC) counterpart, the m-NiSe2/CFC film exhibits even stronger chemisorption, higher catalytic activity and faster reaction kinetics, thereby resulting in significantly improved lithium storage performance. The Al@S/rGO@m-NiSe2/CFC cell has high reversible capacities (1646 mAh g-1 at 0.2C), high QL/QH ratio (3.00 at 0.2C), high rate capability (900 mAh g-1 at 4C), and outstanding cycling stability (a low capacity decay of 0.028% per cycle for 600 cycles at 4C). Moreover, the symmetrically sandwiched cathode of m-NiSe2/CFC@S/rGO@m-NiSe2/CFC is designed for high sulfur loading LSBs (4.5 mg cm-2) with superior electrochemical performance (3.73 mAh cm-2 after 100 cycles at 1C rate). Our work opens up a new opportunity to enhance electrochemical performance of LSBs by phase engineering of NiSe2 catalyst in sandwiched structural cathodes.