Electrochemical systems are essential to modern life. They encompass energy technologies like batteries and fuel cells as well as systems for desalination, mineral extraction, and chemical sensors. The fundamental physics of these systems relies on two components: electrodes and an electrolyte. You might be familiar with electrolytes in the context of sports drinks. Fundamentally, a liquid electrolyte, whether in a drink or an electrochemical device, is an ionic salt solution like dissolved sodium chloride.