Ultrafast aqueous Cs−ion storage kinetics in restacked 1T–MoS2 films

Restacked two-dimensional (2D) material thin films offer a promising approach for achieving high volumetric energy density supercapacitors, but their ultimate rate performance is constrained by electrolyte ion transport properties. This work systematically investigates the electrochemical behaviors and underlying mechanisms of restacked 1T−MoS 2 films in various aqueous electrolytes. In 1 M CsCl electrolyte, an 8.5-μm-thick 1T−MoS 2 film electrode exhibits ultrafast ion storage kinetics with a b -value of 0.94 and a remarkable volumetric capacitance ( C v ) of 221 F cm −3 at 1,000 mV s −1 , significantly outperforming other ionic systems. The electrode also demonstrates excellent cycling stability with 87% capacitance retention after 10,000 cycles at 10 A g −1 . Compared to reported advanced graphene, MXene, and oxide-based electrodes, the 1T−MoS 2 film electrodes in 1 M CsCl show an integrated advantage of ultrathin characteristic and ultrahigh C v under considerable high scan rates of 500 to 1,000 mV s −1 . Theoretical calculations reveal that Cs + possesses the lowest diffusion barrier between 1T−MoS 2 interlayers, where its weak solvation effect facilitates rapid ion storage kinetics. This work not only elucidates the ultrafast transport mechanism of Cs + within confined 2D spaces, but also provides insights into developing next-generation ultrafast energy storage devices with high volumetric energy densities through optimized electrolyte–electrode synergy. The electrochemical ion storage behaviors and underlying mechanisms of restacked 1T−MoS 2 film electrodes in various aqueous electrolytes were systematically investigated. The electrodes exhibit ultrafast charge storage kinetics in 1 M CsCl, demonstrating the combined advantages of ultrathin feature and ultrahigh volumetric capacitance at scan rates as high as 1000 mV s −1 , significantly outperforming state-of-the-art reported electrode materials. Download: Download high-res image (188KB) Download: Download full-size image