High-Power Polysulfide Redox Flow Batteries via an Interfacial Electron Field on a 2D Mesoporous Heterojunction
Jinji Lan, Shu Zhang, Le Yang, Chunjun Chen, Huilei Wu, Liubin Feng, Dong‐Li An, Jiajia Chen
Abstract
Due to the high solubility and multielectron transfer capabilities of polysulfides, aqueous polysulfide redox flow batteries (PS-RFBs) have emerged as promising candidates for large-scale energy storage, offering both low cost and high capacity. However, the sluggish electrochemical kinetics of polysulfides leads to significantly high polarization and low energy efficiency. Here, we tailor a two-dimensional ordered mesoporous nitrogen-doped carbon@MoS 2 (Meso-NC@MoS 2 ) heterojunction with a sandwich-like nanostructure to accelerate the redox kinetics of polysulfides. The in-plane electric field in Meso-NC@MoS 2 optimizes polysulfide adsorption and establishes a directional charge transfer channel, thereby enhancing electron transport from Meso-NC@MoS 2 to S 4 2– and consequently improving the reaction kinetics activity of S 4 2– on the electrocatalyst. As a result, the Meso-NC@MoS 2 based PS-RFBs exhibit a reduction in charging overpotential of approximately 377 mV compared to blank carbon felt, while the battery energy efficiency increases from 42.28% to 85.75% at 20 mA cm –2 . Additionally, the battery can demonstrate a high-power density of 112 mW cm –2, as well as operating for up to 3200 cycles in 30 days with a high Coulombic efficiency of 99.9% at 60 mA cm –2 .