Janus-mask-defined printing enables high-resolution MXene micro-supercapacitors with outstanding energy density

Owing to their high carrier mobility and large surface area, two-dimensional (2D) materials are ideal electrodes for various micro-energy storage devices, enabling advanced on-chip power for integrated electronics. However, the miniaturization of micro-energy storage devices based on 2D materials remains constrained by the challenges in high-throughput patterning of high-resolution electrodes and reliable integration across diverse substrates. Here, we report a Janus-mask-defined printing method to pattern high-resolution MXene electrodes. The Janus mask, with its asymmetric wettability, enables effective control over Ti₃C₂T_x MXene ink flow, resulting in uniform electrode micro-patterns that are sharp and continuous. As a result, the patternable feature size of the electrodes improved from the millimeter scale to 80 μm. High-resolution electrodes can be transferred onto diverse substrates via a capillary-assisted transfer process. With a LiTFSI-based polymer electrolyte, the assembled micro-supercapacitor (MSC) exhibits a high areal capacitance of 4.57 mF·cm⁻² and a volumetric capacitance of 169.23 F·cm⁻³. The volumetric energy density reaches 76.72 mWh·cm⁻³, which outperforms most reported MXene-based MSCs. We also integrated a flexible MSC module as an on-chip power source for a force sensor, producing a self-powered sensor system. This work provides an effective route for high-resolution patterning and scalable transfer of a broad range of nanomaterials beyond MXenes.