An electrochemical cell is described that includes (a) a first electrode; (b) a second electrode; and (c) a channel contiguous with at least a portion of the first and the second electrodes. When a first liquid is contacted with the first electrode, a second liquid is contacted with the second electrode, and the first and the second liquids flow through the channel, a parallel laminar flow is established between the first and the second liquids. Electronic devices containing such electrochemical cells and methods for their use are also described.