Photo-motivated heterojunctions coupling built-in electric field stimulating sulfur redox kinetics for lithium-sulfur batteries
Photo-motivated heterojunctions coupling built-in electric field stimulating sulfur redox kinetics for lithium-sulfur batteries
Research Abstract
Enhancing the redox kinetics of polysulfides in lithium-sulfur batteries (Li-Ss) by photo-irradiation represents a practical approach. Herein, a photo-assisted rechargeable Li-Ss featuring BVO (BiVO4)/Co3O4heterojunctionnanosheets as a multifunctional cathode is designed. The photogenerated electron-hole pairs in BVO synergistically enhance polysulfide redox kinetics during both charging and discharging. Notably, the internal electric field created by BVO/Co3O4 interface effectively suppresses carrier recombination. Photogenerated electrons accelerate the reduction of S8 to Li2S, while holes promote the oxidation of Li2S to S8. As a result, significant specific capacity enhancement to 1550 mAh/g at 0.5 mA cm−2 is observed. Strikingly, the soft pack batteries can achieve a capacity of 300 mAh/g only by illumination. This research offers a promising avenue for enhancing polysulfide redox kinetics by harnessing and storing solar energy.