An electrochemical compressor incorporates an electrochemical cell having an anode and a cathode that reacts a working on the anode side into an ionic component and a reactant. The ionic component is transported through an ion conducting media to the cathode. At least a portion of the reactant passes through a reactant conduit that extends from the anode to the cathode. A transfer device, such as a pump or venturi valve configured along the reactant conduit allows the reactant to flow from the anode to the cathode. The reactant and the ionic component are reacted on the cathode to reform the working fluid. A reactant separator may be configured to selectively allow reactant into the reactant conduit. A reactant separator may be a perm-selective layer or a fluid that has high reactant solubility. The working fluid may be water with the ionic component protons and the reactant oxygen.