Lithium ion batteries are energizing the current mega trend towards electrical mobility. One of the key requirements of lithium ion batteries is that they must be free of water, because water reacts with the conducting salt of the electrolyte. A proven and reliable method to measure the water content in the electrolyte matrix of lithium ion batteries directly is coulometric Karl Fischer titration.
All batteries consist of an anode and a cathode, a separator as well as an electrolyte. Electrical conductivity between anode and cathode is established by the electrolyte. In general, mixtures of anhydrous, aprotic solvents and lithium salts are chosen for such electrolytes. However, if there is water present in the electrolyte, it will react with the conducting salt, e.g., LiPF6. This leads to the formation of highly toxic hydrofluoric acid.