A Composite Of Conip Quantum Dot-Decorated Reduced Graphene Oxide As A Sulfur Host For Li-S Batteries

The "shuttle effect" and sluggish reaction kinetics of lithium polysulfides lead to inferior cycling performance and rate capability of Li-S batteries, which impede their practical application. Herein, a composite of CoNiP quantum dot-decorated graphene oxide (CoNiP-rGO) was designed and prepared and used as a sulfur host in Li-S batteries. SEM and TEM images show that countless CoNiP quantum dots (CoNiP-QDs) are uniformly dispersed on the rGO nanosheets. Density functional theory (DFT) calculations certify the metallic property and high activity of the CoNiP-QDs. At the same time, the rGO enhances the electronic conductivity of the electrode and ensures uniform dispersion of the CoNiP-QDs. Benefitting from the CoNiP-QDs and rGO, compared with the CoP or NiP sulfur hosts reported in the literature, the CoNiP-rGO host demonstrates obvious advantages in specific capacity and cycle stability. The Li-S battery with the CoNiP-rGO/S cathode demonstrates a high capacity of 598.2 mA h g(-1) at 3C rate. At the same time, it delivers excellent cycle-performance with a capacity decay rate of 0.08% after 600 cycles at 1C rate. This work provides a simple and universally applicable method for manufacturing metal phosphide quantum dot/rGO as a sulfur host for Li-S batteries.