a, Scanning electron microscope image of restacked 1T phase 2D MoS2 film. b, The electrochemical system consists of a working electrode (the actuator) along with a counter electrode (Pt) and a reference electrode (standard calomel electrode, SCE) submerged in 0.5 M H2SO4. c, Images of curvature induced by charge intercalation in free-standing (that is, no Kapton beam) 1T MoS2 film on gold (scale bar, 1 cm). d, e, Diagram (d) and photograph (e) of actuation in forward and backward directions by modulation of the electrode potential between -0.3 V and + 0.3 V.
Actuators that convert electrical energy to mechanical energy are useful in a wide variety of electromechanical systems and robotics. Nonporous metal as well as graphite have been implemented in actuation applications. Although high strains can be achieved, but actuation only operates at high voltages (3-3.4 V) and very low frequencies (mHz range).
Researchers at Rutgers University have invented a novel macroscopic actuation device made of (2D) 1T phase molybdenum disulfide (MoS2) nanosheets-coated flexible films that can operate at low voltages (+0.3 to –0.3 V) and frequencies up to 1 Hz. The mechanism of actuation is the insertion and removal of cations between nanosheets of (2D) 1T phase MoS2 under electrochemical induction of +0.3 to –0.3V. The MoS2 films are able to generate mechanical stresses of ~ 17 MPa – higher than mammalian muscle (~0.3 MPa) and comparable to ceramic piezoelectric actuators (~ 40 MPa). The actuation performance is attributed to the high electrical conductivity of the metallic 1T phase of MoS2 nanosheets, the elastic modulus of restacked MoS2 layers and fast proton diffusion between the nanosheets.
Electromechanical systems and robotics such as steerable catheters for biomedical applications, adaptive wings for aircrafts, or drag-reducing wind turbines.
- High displacement
- High generated force
- Low potential
- High frequency (1 Hz)
Intellectual Property & Development Status:
Patent pending. Available for licensing and/or research collaboration.
Metallic molybdenum disulfide nanosheet-based electrochemical actuators. Acerce M, Akdoğan EK and Chhowalla M. (2017) Nature 549: 370-373.