NiS2 nanoparticles decorated hierarchical porous carbon for high-performance lithium-selenium batteries

lithium–selenium (Li–Se) batteries are recognized as an attractive candidate for energy storage owing to its high volumetric capacity (3253 mA h cm−3). However, the sluggish electrochemical redox reaction and the accompanying enormous volume fluctuation greatly impede the application of Li–Se batteries. Herein, a catalyst of nickel disulfide (NiS2) nanoparticles decorated hierarchical porous carbon (HPC) has been fabricated and applied as the cathode for Li-Se batteries. The porous structure offers large amount of viod to buffer the volume change during charge/discharge. At the same time, the NiS2 nanoparticles exhibit strong adsorption capabilities towards lithium polyselenides and aslo promote the conversion of these intermediates. As a consequence, the NiS2-HPC cathode delivers a superior rate capacity (569 mAh g−1 at 0.5 C and 549 mAh g−1 at 1 C) and good cycling stability (289 mAh g−1 after 1000 cycles at 2 C with a Coulombic efficiency of ∼100%). This work demonstrates the viability of employing metal sulfide-anchored porous carbon materials for high-performance lithium-selenium batteries.