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

The incorporation of catalytic components is a promising strategy to promote redox reaction kinetics and suppress polysulfide shuttling for high-performance lithium-sulfur batteries (LSBs). In this work, metastable marcasite NiSe2 nanodendrites grown on carbon fiber clothes (m-NiSe2/CFC) were synthesized to improve chemical adsorption and electrocatalytic activity towards lithium polysulfides. The multifunctional m-NiSe2/CFC film was utilized as both the interlayer and the three-dimensional (3D) current collector in LSBs. In comparison with the stable pyrite NiSe2 nanodendrite-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 a high reversible capacity of 1646 mA h g-1 at 0.2C, a high QL/QH ratio of 3.00 at 0.2C, a high rate capability of 900 mA h g-1 at 4C, and an outstanding cyclic stability exhibiting a low capacity decay of 0.028% per cycle for 600 cycles at 4C. Moreover, a symmetrically sandwiched cathode of m-NiSe2/CFC@S/rGO@m-NiSe2/CFC was designed for high sulfur loading LSBs (4.5 mg cm-2) with superior electrochemical performance of 3.73 mA h cm-2 after 100 cycles at 1C rate. Our work opens up a new opportunity to enhance the electrochemical performance of LSBs by phase engineering of NiSe2 catalysts in sandwiched structural cathodes.