Interface-confined etching towards mesoporous two-dimensional MoO3−x for high-performance planar supercapacitors

Abstract

Two-dimensional transition metal oxides (2D TMOs) have drawn broad interest owing to their great potential for catalysis and energy storage applications, but suffered restacking and poor conductivity. Porous and conductive nanosheets are highly required, while suffering from inefficient synthesis. Here, we demonstrate interface-confined etching to synthesize mesoporous 2D metal oxides. Ultrathin porous MoO_3−x nanosheets are successfully synthesized with 2–3 nm thickness and abundant 3–5 nm diameter mesopores, ensuring high specific surface area and 10⁹-time improved conductivity when compared to the pristine sample. Consequently, 2D MoO_3−x delivers ultrahigh volumetric specific capacitance of 2003.2 F cm⁻³ and energy density of 94.1 Wh L⁻¹ at high power density of 1120 W L⁻¹, demonstrating great promise for energy storage. This work provides a promising way to synthesize 2D materials for high-performance energy storage.