Plasma Technologies for Water Electrolyzers

Abstract

Problems of construction material oxidation/corrosion, hydrogen permeation, and embrittlement become especially important at high-pressure electrolysis. Ion implantation and magnetron sputtering application possibilities for electrocatalysts and protective coating synthesis have been numerically estimated and tested mainly for PEM electrolysis. Stability of cathode materials based on titanium has been increased up to 3–4 times with carbon and nitrogen ion implantation. In case of anode titanium materials (current collectors, bipolar plates), Pd and Pt ion implantation was used for anticorrosion and antioxidant protection. Two energy ranges were examined: 40–50 keV and 1–5 keV. The first range energy ion penetration into Ti was more than 100 nm, but the surface concentration (even at dose about 10¹⁷ ions/cm²) was rather small to protect Ti from an intensive oxidation. The surface concentration of implanted ion of the second energy range has been increased up to 20%, but the modified layer thickness was rather small for high surface layer stability. Combination of high- and low-energy implantation modes has permitted to reach rather high surface stability with a rather high lifetime (increased more than one order in model experiments) at Pt (Pd) concentrations less than 0.02 mg/cm². For bipolar plates and current collectors of porous Ti, a combined technology based on magnetron sputtering of Pt (Pd) assisted by ion (Ar, N, O) implantation has demonstrated even more efficient results due to additional chemical and radiation surface modification but at slightly larger platinum metal loadings. Magnetron sputtering assisted by ion implantation appeared to be also rather efficient for catalyst layer synthesis for PEM and alkaline electrolyzers.