A three-chamber electrochemical cell comprises a central chamber, first and second chambers, and a central part for conveying a fluid solution into and out from the central chamber, the central part being symmetric with respect to a mid-plane of the cell. First and second electrodes of the cell are in surface contact with, respectively, first and second membranes. The first and second electrodes are produced from a porous electrically conductive material that absorbs mechanical stresses due to a first pressure differences between the first side chamber and the central chamber, and a second pressure difference between the second side chamber and the central chamber. The first and second electrodes are produced from a material including micrometer-sized metal beads compacted with one another leaving interstices between the beads, which form the pores of said electrodes.