MOF-Derived Bifunctional Co0.85Se Nanoparticles Embedded in N-Doped Carbon Nanosheet Arrays as Efficient Sulfur Hosts for Lithium-Sulfur Batteries.

Lithium-sulfur batteries possess the merits of low cost and high theoretical energy density but suffer from the shuttle effect of lithium polysulfides and slow redox kinetics of sulfur. Herein, novel Co0.85Se nanoparticles embedded in nitrogen-doped carbon nanosheet arrays (Co0.85Se/NC) were constructed on carbon cloth as the self-supported host for a sulfur cathode using a facile fabrication strategy. The interconnected porous carbon-based structure of the Co0.85Se/NC could facilitate the rapid electron and ion transfer kinetics. The embedded Co0.85Se nanoparticles can effectively capture and catalyze lithium polysulfides, thus accelerating the redox kinetics and stabilizing sulfur cathodes. Therefore, the Co0.85Se/NC-S cathode could maintain a stable cycle performance for 400 cycles at 1C and deliver a high discharge specific capacity of 1361, 1001, and 810 mAh g-1 at current densities of 0.1, 1, and 3C, respectively. This work provides an efficient design strategy for high-performance lithium-sulfur batteries with high energy densities.