Electrochemical Actuators Based on Two-Dimensional Ti₃C₂T_<i>x</i> (MXene)

Electrochemical actuators are devices that convert electrical energy into mechanical energy via electrochemical processes. They are used in soft robotics, artificial muscles, micropumps, sensors, and other fields. The design of flexible and stable electrode materials remains a major challenge. MXenes, an emerging family of 2D materials, have found applications in energy storage. Here, we report an actuator device using MXene (Ti₃C₂T_x) as a flexible electrode material. The electrode in 1 M H₂SO₄ electrolyte exhibits a curvature change up to 0.083 mm^-1 and strain of 0.29%. Meanwhile, the MXene-based actuator with a symmetric configuration separated by gel electrolyte (PVA-H₂SO₄) has curvature and strain changes up to 0.038 mm^-1 and 0.26% with excellent retention after 10,000 cycles. In situ X-ray diffraction analysis demonstrates that the actuation mechanism is due to the expansion and shrinkage of the interlayer spacing of MXenes. This research shows promise of this new family of materials for electrochemical actuators.