today's applications, most biomonitoring electrodes are silver/silver chloride sensors which are fabricated by coating a thin layer of silver on plastic substrates while the outer layer of silver is converted to silver chloride. The principle of silver/silver chloride sensors operation is the conversion of ion current at the surface of human tissues to electron current to be delivered through an electrical wire to the measurement instrument. An important component of the operation is the electrolyte gel applied between the electrode and the tissues. The gel contains free chloride ions such that the ion charge can be carried through the electrolyte solution. Therefore, the electrolyte solution has the same conductivity for the ion current as the human tissues. When the ion current develops, the metallic silver atoms (Ag(s)) of the electrode oxidize and it releases cations to the solution while the discharged electrons carry the electrical charge through the electrical wire. At the same time, the chloride anions () present in the electrolyte solution travel towards the anode (positively charged electrode) where they are precipitated as silver chloride (AgCl) as they bond with the silver cations () present onto the Ag(s) electrode surface. The reaction allows the ion current to pass from the electrolyte solution to the electrode while the electron current passes through the electrical wire connected to the measuring instrument. When there is an uneven distribution of cations and anions, there will be a small voltage called half-cell potential associated with the current. In the direct current (DC) system that is used by the ECG and EEG instruments, the difference between the half-cell potential and the zero potential is shown as DC offset which is an undesirable characteristic. Silver/silver chloride is a common choice of biological electrodes due to its low half-cell potential of about +222 mV (SHE), low impedance, with a toxicity lower than that of the calomel electrode containing mercury. Elevated temperature application When appropriately constructed, the silver chloride electrode can be used up to 300 °C. The standard potential (i.e., the potential when the chloride activity is 1 mol/kg) of the silver chloride electrode is a function of temperature as follows: Bard et al. give the following correlations for the standard potential of the silver chloride electrode between 0 and 95 °C as a function of temperature (where t is temperature in °C): The same source also gives the fit to the high-temperature potential between 25