A mercury cell is a type of electrochemical cell that utilizes a liquid mercury electrode and other materials like zinc to create electricity. Synonyms for mercury cell include mercury battery, wet cell, mercury oxide battery, and cathode-ray tube. Mercury batteries were once widely used in small electronic devices such as hearing aids and calculators. However, due to the toxic nature of mercury, the use of mercury cells has been phased out in many countries. The development of alternative materials and technologies has led to the replacement of mercury cells with more environmentally friendly solutions, such as alkaline and lithium-ion batteries.