Constructing In-Plane Pores in MXene/1T-MoS2 Films for High-Performance Sodium-Ion Capacitor

Transition metal carbides/nitrides (MXene) films are promising electrodes because of their high conductivity and excellent mechanical properties. Combining the formation of in-plane pores with the introduction of spacers results in vertically and horizontally interwoven ion transport pathways, improving ion diffusion kinetics and exposing more internal electrochemically active sites. Herein, a Cu2+-induced in situ etching strategy was employed to prepare in-plane porous-Ti3C2Tx MXene micron-flakes, which were vacuum filtered to fabricate porous-Ti3C2Tx/1T-molybdenum disulfide (MoS2) films. The 1T-MoS2 nanosheets functioned as spacers to prevent restacking and increase ion and charge storage space. More importantly, the in-plane pores served as vertical ion-conducting channels, resulting in direct vertical channels with reduced vertical ion-path tortuosity, enabling rapid vertical ion diffusion. Remarkably, at a high current density of 30 mA cm–2, the volumetric capacitance of the porous-Ti3C2Tx/1T-MoS2 film was as high as 908.5 F cm–3, nearly 14 times that of the pristine MXene film, demonstrating improved capacitance.