Electrochemistry theme is a component of Encyclopedia of Physical Sciences, Engineering and Technology Resources in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty one Encyclopedias. Electrochemistry is the science that studies the properties and chemical transformations of/within ionic conductors (most commonly a solution of a salt) and at the interface between an ionic conductor and an electronic conductor (most commonly a metal) or semiconductor. Electrochemistry is present in many aspects of our everyday life. Probably, batteries are the most common example. However, electrochemistry is also present in many other aspects of vital importance in the chemical industry, like chlorine, caustic soda and aluminum (and many others not described here) are produced through electrochemical processes. This volume is aimed at the following five major target audiences: University and College students Educators, Professional practitioners, Research personnel and Policy analysts, managers, and decision makers and NGOs