V2O5 nanofibre sheet actuators

Abstract

Vanadium oxides, such as V₂O₅, are promising for lithium-ion batteries^1,2, catalysis³, electrochromic devices^4,5 and sensors^6,7. Vanadium oxides were proposed more than a decade ago for another redox-dependent application: the direct conversion of electrical energy to mechanical energy in actuators (artificial muscles)⁸. Although related conducting polymer^8,9 and carbon nanotube actuators¹⁰ have been demonstrated, electromechanical actuators based on vanadium oxides have not be realized. V₂O₅ nanofibres^6,11 and nanotubes¹² provide the potential advantages of low-cost synthesis by sol–gel routes and high charging capacity and long cycle life^13,14. Here, we demonstrate electromechanical actuation for obtained high modulus V₂O₅ sheets comprising entangled V₂O₅ nanofibres. The high surface area of these V₂O₅ sheets facilitates electrochemical charge injection and intercalation that causes the electromechanical actuation. We show that the V₂O₅ sheets provide high Young's modulus, high actuator-generated stress, and high actuator stroke at low applied voltage.