Search

[Display omitted] • Plum blossom-like CoSe 2 /N-doped carbon nanotubes S host was synthesized. • DFT calculation confirms the catalytic performance of CoSe 2 for Li 2 S x conversion. • The plum blossom-like structure is beneficial to the diffusion of electron/Li+. • DFT calculation confirms the chemical adsorption of CoSe 2 to Li 2 S x. • The CoSe 2 /hNCTs/S cathode delivers satisfactory lithium storage performance. Lithium-sulfur batteries (LSBs) have attracted wide attention as one of the most potential secondary batteries in the next generation. However, the low sulfur utilization, serious "shuttle effect", and large volume expansion of the sulfur cathode restrict the performance of LSBs. Here, CoSe 2 decorated hollow N-doped carbon nanotubes (CoSe 2 /hNCTs) were synthesized firstly, and then the CoSe 2 /hNCTs were used as a sulfur host to prepare a multifunctional CoSe 2 /hNCTs/S cathode. DFT calculations confirm that the CoSe 2 not only efficiently adsorbs lithium polysulfides (LiPSs), but also exhibits good catalytic performance for the conversion of LiPSs. SEM and TEM images indicate that the CoSe 2 uniformly disperses on the surface of the polypyrrole nanotube-derived hNCTs, like plum blossoms. The hNCTs with a morphology of plum blossom branches provide a high conductive network and prohibit large volume expansion during the electrochemical process. And the plum petal-like CoSe 2 on the hNCTs surface acts as a catalyst and an efficient polysulfides trap. The CoSe 2 /hNCTs/S cathode delivers a satisfactory lithium storage performance, which presents reversible capacities of 1156 and 640 mA h g−1 at 0.5 and 5C, respectively. Simultaneously, the cathode demonstrates excellent cycle stability with a slow capacity decay rate of 0.069% per cycle in 1000 cycles at 1C rate. This work provides a new idea for constructing composites of transition metal selenides and carbon materials, promoting the practical applications of LSBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multi-functional electrocatalyst of CoOOH/hollow carbon sphere (PHCS) was synthesized. • DFT calculation confirms the catalytic performance of CoOOH for Li 2 S x conversion. • DFT calculation certificates the promotion of CoOOH on OER reaction kinetic. • The CoOOH-PHCS cathode delivers satisfactory lithium storage performance. • The CoOOH-PHCS demonstrates excellent OER and ORR activity in the alkaline electrolyte. Materials with excellent electrocatalytic properties play an important role in the field of electrochemistry. In this work, a multi-function electrocatalyst of cobalt oxyhydroxide decorating homogeneous porous hollow carbon sphere (CoOOH-PHCS) was designed and fabricated. The CoOOH-PHCS can not only be used as an electrocatalyst to inhibit the shuttle effect in Li-S batteries (LSBs), but also can effectively accelerate the reaction kinetics in oxygen reduction/evolution reactions (ORR/OER). Meanwhile, density functional theory (DFT) calculations were performed to investigate the electrocatalytic activity of the CoOOH-PHCS. Benefiting from the synergy effect of CoOOH and PHCS, the CoOOH-HPC/S electrode exhibits a low capacity decay of 0.04% per cycle in 450 cycles at 1C. Meanwhile, the CoOOH-PHCS demonstrates excellent OER and ORR activity in the alkaline electrolyte. This work explores and reveals the application potential of CoOOH in electrocatalytic field. [ABSTRACT FROM AUTHOR]