Researchers at Anhui University have developed a flexible, self-powered tactile sensing system using a holey MXene paste, achieving precise pressure detection and user recognition without external power.
Currently, flexible electronics rely on integrating sensing and energy units on a flat 2D plane. But this reliance often leads to bulky array layouts, complex wiring, and inefficient space utilization, hindering efforts to miniaturize and scale the technology.
Monolithic 3D integration, inspired by semiconductor stacking, offers higher density in smaller footprints. However, flexible systems introduce new challenges: material mismatches, weak interconnects, and instability under bending.
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The Answer is in Holey MXene Paste
MXenes, particularly titanium carbide (Ti3C2Tx), provide conductivity, mechanical flexibility, and dual functionality for both sensing and energy storage applications.
The “holey” version, engineered with in-plane mesopores, enhances ion transport, increases active sites, and prevents nanosheet stacking. This allows the material to function as a sensor, electrode, collector, and interconnect all at once. With this capacity, such electronics will be essential for building vertically integrated systems with fewer interface mismatches.
One Device, Two Functions
Inspired by human skin’s Merkel cells, the team built vertical one-body units (VOUs) that act as both microsupercapacitors and pressure sensors.
These VOUs are created from the same holey MXene paste and are vertically stacked using blade-coating and stamping methods, which are compatible with large-area, low-cost manufacturing.
Each unit delivers real-time pressure sensing while storing energy, eliminating the need for external power.
The system's circuit design ensures ultra-low power consumption. When idle, its high internal resistance minimizes current draw. Only under pressure do ion channels open, reducing resistance and producing a measurable signal - still with minimal power use.
Building and Testing the Sensor
The VOUs were fabricated by laser-engraving MXene-based paper into interdigital electrodes, electrodepositing zinc, spraying a cellulose nanofiber (CNF) barrier, adding gel electrolyte, and encapsulating with PET.
The result is a compact, flexible sensor unit that offers both mechanical stability and electrical responsiveness.
The team measured fast response and recovery times (of less than 100 milliseconds), high sensitivity, and strong performance under varied pressures and frequencies. Surface-patterned gel electrolytes tuned via sandpaper molds improved linearity, detection range, and switching ratios.
The sensor was integrated into a smart access control system that identifies users by analyzing their unique pressing behaviors.
A backpropagation neural network extracted 14 behavioral features: press duration, intervals, and amplitude, from password inputs. The system reached 98.67 % accuracy, highlighting its potential in personalized security.
In real-time applications, the sensor could control LED brightness via pressure and map touch input across 3×3 arrays, demonstrating its suitability for interactive devices and wearable technology.
Environmentally Conscious Design
Beyond performance, the system is environmentally degradable.
The MXene electrodes break down in hydrogen peroxide within 72 hours; the gel electrolyte dissolves in water within 3 hours.
These results highlight this system's potential in eco-friendly electronics.
The study offers a compelling framework for intelligent, sustainable, and scalable flexible electronics. Future research may incorporate other sensing modes, such as temperature or humidity, and extend applications to biomedical monitoring and personalized robotics.
Journal Reference
Wang, M. et al. (2026). Flexible Monolithic 3D-Integrated Self-Powered Tactile Sensing Array Based on Holey MXene Paste. Nano-Micro Letters, 18, 68. DOI: 10.1007/s40820-025-01924-9
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