An electrochemical device having a liquid electrolyte which includes a protic solvent, an anode electrode disposed in contact with the liquid electrolyte, and a cathode electrode disposed in contact with the liquid electrolyte. A membrane which interrupts the transport of ions between the electrodes at a predetermined temperature is disposed in the liquid electrolyte between the anode electrode and the cathode electrode. In this way, electrochemical devices such as batteries, fuel cells, electrolyzers, and sensors, which may overheat during use and cause a fire or explosion, are precluded from overheating.