0D–1D–2D Multidimensional Heterostructure Films for High-Performance Flexible Microsupercapacitors

Planar microsupercapacitors (MSCs) are of great value for flexible and wearable electronics. The rational design of electrode materials with rapid ionic kinetics and sufficient active site exposure is critical but challenging for realizing high-energy MSCs. Herein, we report the dot-tube-sheet multidimensional heterostructure films (MHFs) with versatile patterns by a simple mask-assisted strategy, consisting of 0D carbon dots (CDs), 1D carboxyl-carbon nanotubes (c-CNTs), and 2D Ti₃C₂ MXene nanosheets. Thanks to the high electrical conductivity, enlarged interlayer spacing, abundant porous channels, and excellent mechanical strength, the CDs/c-CNTs/Ti₃C₂ MHF electrodes deliver a remarkable areal capacitance of 1162.6 mF cm^-2 at 0.8 mA cm^-2 and prominent cycling stability (107.1% capacitance retention after 10,000 cycles) in a 1 M H₂SO₄ electrolyte. Moreover, the fabricated solid-state CDs/c-CNTs/Ti₃C₂ MSCs achieve a high energy density (11.1 mWh cm^-2) and long-term cycling lifespan (102.1% capacitance retention after 8000 cycles), superior to those of state-of-the-art MSCs. The parallel and serial interconnected modular power sources highlight the potential for powering the actual energy consumption products.