Abstract
? 2022 Elsevier B.V.The combination of chemical immobilization and accelerated conversion has been certificated as the most effective method to inhibit the shuttle effect. However, it remains challenging to clarify the electrochemical reduction pathways under the action of the catalyst. Here, the nickel phosphide nanosphere with reduced graphene oxide (Ni2P/rGO) as a bifunctional catalyst is proposed to anchor and catalyze the conversion of polysulfides. With a robust porous structure, the high specific surface area as well as the preponderant electrical conductivity, Ni2P/rGO can increase the active sites significantly and accelerate effectively the electron/ion transport, indicative of the accelerated conversion kinetics of polysulfides. Besides, Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical impedance spectroscopy (EIS) spectra at different discharge depths were used to analyze the sulfur reduction pathways under different catalysts, suggesting that Ni2P/rGO effectively enhances the kinetics of reduction reaction and reduces the energy barrier of the end products (Li2S) nucleation. Given these, upon a high sulfur loading of 5.3 mg cm?2, the Ni2P/rGO based electrode delivers a high area capacity of 4.067 mAh cm?2 at 0.2 C with excellent stability. This work provides an idea for studying the discharge mechanism of Li-S batteries.
NSTL
Elsevier