Clark cell

battery

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June 24, 2026

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The Clark cell is a type of primary battery that was historically used as a standard for electromotive force. It features zinc amalgam and mercury as electrodes, with zinc sulfate serving as the electrolyte. At 15°C, its electromotive force is approximately 1.4328 volts. This cell was invented by English engineer Josiah L. Clark.1

Another related primary cell is the Daniell cell, which has a constant electromotive force of about 1.1 volts. It uses copper in a copper sulfate solution and zinc in dilute sulfuric acid or zinc sulfate, with the two solutions separated by a porous partition. Both the Clark and Daniell cells are examples of primary batteries, which are non-rechargeable.21

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Other primary battery systems
…predictable standard voltage are the Clark cell (zinc–mercurous sulfate–mercury; 1.434 volts) and the Weston cell (cadmium–mercurous sulfate–mercury; 1.019 volts). Magnesium–silver chloride and magnesium–lead chloride batteries are commonly employed in undersea operations where the salt water becomes the electrolyte when the battery is submerged or in situations where low risk to…
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…predictable standard voltage are the Clark cell (zinc–mercurous sulfate–mercury; 1.434 volts) and the Weston cell (cadmium–mercurous sulfate–mercury; 1.019 volts). Magnesium–silver chloride and magnesium–lead chloride batteries are commonly employed in undersea operations where the salt water becomes the electrolyte when the battery is submerged or in situations where low risk to…
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