Aqueous salt solution Cell performance 1 Degradation 1 Deionised waters 1 Deionized water 1 Electrolysis 1 Electrolytic cells 1 Electrolyzers 1 Ion exchange membranes 1 Maintenance cost 1 Performance 1 Potassium hydroxide 1 Proton exchange membrane electrolyzers 1 Residual salts 1 Switching 1 System costs 1 Water operations 1