Regulating the microstructure and catalytic activity of metal selenides via calcination strategy for lithium-sulfur battery

Metal selenides obtain a series of advantages such as high electronic conductivity, excellent catalytic activity and facile fabrication approach, which are considered as promising catalysts in lithium sulfur (Li-S) battery. Traditional research based on metal selenides focuses on designing novel/complex microstructures or composites, however, the catalytic ability can be greatly affected by internal properties such as defect or vacancy. In this work, hollow nickel-cobalt layered double hydroxide (NiCo-LDH) is first fabricated and applied as a precursor to fabricate NiCoSe, and Se vacancy accompanied with crystal phase, microstructure and catalytic activity can be regulated by simply adjusting selenization atmosphere and temperature. Involving the application of NiCoSe in Li-S battery, the optimum fabrication parameter is perform the selenization at 600 °C under argon/5 % hydrogen, and the battery can exhibit a high discharge specific capacity of 1042.8 mAh g−1, excellent cycling performance of 500 cycles with a decay rate of 0.083 % at 1 C. This work highlights the importance of calcination process and also provides reference for further modifying the microstructure and performance of metal selenides in Li-S battery.