▎ 摘　　要

NOVELTY - The electrochemical cell has: a fuel source; an oxidation source; a positive electrode exposed to an electrolyte membrane; and a negative electrode exposed to the electrolyte membrane. The electrolyte membrane is positioned between the positive and negative electrodes, and has an electron donor material and a shunt material having specific volume percentage of carbon-containing semiconductors that become electronically conductive at a specific shunting onset potential below the cell's open circuit potential. USE - Electrochemical cell such as a polymer-electrolyte-membrane fuel cell. ADVANTAGE - The electrochemical cell incorporates a shunt into the membrane separator that becomes electronically conductive around a well-defined anodic onset potential, thus preventing excessive anodic potentials at the positive electrode that would otherwise drive deleterious parasitic reactions such as catalyst dissolution or catalyst and carbon oxidation. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an electrochemical cell membrane electrode assembly. DESCRIPTION OF DRAWING(S) - The drawing shows a polymer-electrolyte-membrane fuel cell with associated chemical reactions under normal operating conditions. 100Bipolar plate 101Gas diffusion layer 102Cathode 103Polymer electrolyte membrane 104Anode