Dynamics Engineering of Composite MoS2 Electrode Toward Photo-Rechargeable Sodium-Ion Batteries

Photo-rechargeable batteries (PRB) featuring dual-functional electrode system have emerged as a novel solution to address the solar harvest and energy storage in a highly integrated device. Nevertheless, it is a big challenge to really achieve PRB only with light illumination due to a serious dynamics mismatching between the low storage kinetics and instantaneous photo-generated carriers. In this study, a 3D carbon nanotube interconnected MoS 2 nanosheets (CNT-MoS 2 ) are successfully constructed as a dual-functional electrode for photo-rechargeable Na-ion batteries. Theoretically, electrons tend to transfer from the MoS 2 CNTs and accumulate on CNT, while holes tend to accumulate on the MoS 2 . Experimentally, such material exhibits remarkably improved surface potential under light illumination and longer photoluminescence lifetime. It also displays excellent Na-ion storage kinetics in ether-based electrolytes and efficient utilization of photo-generated carriers. As a result, it exhibits significantly enhanced sodium-ion storage capacity under light illumination and a good photoconversion and storage efficiency of 2.56%. Notably, it has a remarkable photo-charging response under zero external bias, reaching a high photo-charging voltage of 2.0 V, while delivering a high capacity of ≈400 mAh g −1 and a reversible photo-charging cycling. This work firstly demonstrates the achievement of real Na-ion PRB through regulating the electrochemical kinetics.