The two electrodes, cathode and anode, are separated by a polymer electrolyte membrane which permits protons to cross to reach the cathode while the electrons are made to flow as part of a circuit to carry an electrical current.

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The resin within the carbon layers is laced with lithium ions, so that each layer acts like an electrode, causing the positively charged lithium ions to collect in one layer when a voltage is applied, and a current to flow when the sandwich is placed in a circuit.

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Despite the support for McEnroe, the flow of young U.S. talent onto the professional circuit remains a trickle rather than the hoped for flood.

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