The history of water electrolysis from its beginnings to the present

The principle of the electrochemical decomposition of water in an electrolysis cell has already been known for more than 230 years. The first generation of hydrogen by electricity was done as early as 1789 by van Troostwijk and Deiman using an electrostatic generator as the direct current source. Shortly after Volta invented the voltaic pile in 1800, Carlisle and Nicholson used such a device to decompose water into hydrogen and oxygen. In the same year, Ritter performed comparable experiments in Jena, Germany. Moreover, Cruickshank used a voltaic pile for the electrochemical decomposition of NaCl to hydrogen and chlorine at the beginning of the 19th century. Nevertheless, it took decades before the processes were used in the first technical applications. Around 1890 Charles Renard constructed a water electrolysis unit to generate hydrogen for French military airships. It is estimated that around 1900 more than 400 industrial alkaline water electrolyzers were in operation worldwide and large-scale deployment of the chlor-alkali process started. Later, different types of commercial alkaline water electrolyzers were developed in the 20th century to generate hydrogen needed to produce ammonia fertilizers based on low-cost hydroelectricity. As the 20th century progressed, the more cost-effective production of hydrogen by steam reforming of methane increasingly replaced water electrolysis, and by the end of the 20th century, the process was only used in niche applications. In the late 1960s the development of proton exchange membrane electrolysis began at General Electric using an acidic fluorinated ionomer as a solid electrolyte. But the technology became established in the following decades only in laboratory, military, and space applications due to the high material costs. At about the same time, General Electric, and the Brookhaven National Laboratory also started to develop high-temperature electrolysis with solid oxide cells. In Germany, Dornier followed in the HOT ELLY project this technology until the mid-1980s. But despite of all technical progress made commercialization of the membrane and solid oxide electrolysis could not be launched in that time. But new interest in water electrolysis was stimulated already in the 1990s as hydrogen was regarded as a green energy carrier for renewable energy sources like wind and solar power and to power fuel cells, e.g., in automotive applications. However, it is only in the last 10 years that we have seen a significant increase in global interest for water electrolysis, with the adoption of ambitious national climate protection programs. Water electrolysis is regarded as the central element for sector coupling and is expected to make an important contribution to reducing greenhouse gas (GHG) emissions close to net-zero by 2050.