A membrane electrode assembly (MEA) comprises substantially concentric and tubular-shaped layers of a cathode, an anode and an ion-exchange membrane. The MEAs of the invention can be used in an electrochemical cell, which comprises the following layers which are tubular-shaped, arranged substantially concentrically, and listed from the inner layer to the outer layer; (i) a cylindrical core; (ii) one of the electrodes; (iii) a membrane; (iv) the other of the electrodes; and (v) an outer cylindrical sleeve.