Abstract: A new and improved electrochemical actuator and method of using it enables a reversible electrochemical generation of gases for inducing a phase/volume change that can produce high actuation forces, long actuation distances, and remain at the last pressure level attained by current flow even after the power is switched off, enabling a zero power hold at any position. The electrochemical actuator includes an electrolyte solution sealed within a substantially constant volume chamber, having electrical contacts disposed therein such that the electrolyte is in electrical communication with the electrical contacts. Passage of current between the contacts through the electrolyte, separates the electrolyte and or electrode material into its component gas or gases, resulting in an increased pressure within the chamber.