Hydrogen, often dubbed the future fuel, is gaining traction as a clean energy source. Among the various methods of hydrogen production, electrolysis of water using renewable energy has emerged as a promising route.
However, development in this field is taking hydrogen production to new depths – quite literally – through the direct electrolysis of seawater. This innovative technology, which can bypass the need for complex desalination processes, is not only a game-changer for hydrogen production but also holds the potential to revolutionize offshore wind power.
A team of researchers led by Wang Erdong, a scientist at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, has achieved a remarkable milestone in this arena. Their 1Nm³/h direct electrolysis seawater hydrogen production unit recently completed over 2000 hours of continuous and stable operation. What’s truly remarkable is the unit’s energy efficiency, with an average DC power consumption of just 4.04 kWh per Nm³ of hydrogen produced.
Direct electrolysis of seawater has long been a goal in hydrogen production, but it’s a complex endeavor. Seawater contains a myriad of ionic components, including chloride ions, magnesium ions, and calcium ions, which can trigger unwanted side reactions such as chlorine precipitation, chlorine corrosion, and solid deposition during the electrolysis process. These side reactions have historically hampered the reliability and efficiency of seawater-based hydrogen production.
The team’s approach involved a comprehensive focus on both fundamental research and engineering development. They tackled the entire hydrogen production chain, from the foundational research and material exploration to system design integration. Overcoming numerous scientific and technical challenges, including catalyst development, electrode reactions, and electrolyte regulation, they succeeded in creating a cohesive system.
This remarkable achievement is underpinned by an impressive array of technological breakthroughs. The team developed advanced chlorine-resistant oxygen evolution electrodes, hydrogen evolution electrodes resistant to calcium and magnesium ion deposition, high-efficiency direct electrolysis seawater hydrogen production electrolyzer design, and intelligent automatic electrolyte concentration control technology. These innovations have resulted in 17 patent applications related to seawater electrolysis for hydrogen production, establishing a robust intellectual property framework around this technology.
The 1Nm³/h direct electrolysis seawater hydrogen production unit, utilizing natural seawater from the Dalian Sea, demonstrated outstanding performance during its 2000+ hours of continuous operation. It maintained an average chamber voltage of 1.69V, remarkable energy efficiency at 4.04 kWh/Nm³ H2, and an oxygen chlorine content of less than 20ppb.
Not content with this achievement, the team is already pushing boundaries further. They’ve developed a new generation of electrolytic seawater hydrogen production electrodes and electrolyzer design technology. This innovation has more than doubled the current density of the electrolyzer under the same electrolysis voltage, further improving efficiency.
Direct electrolysis of seawater for hydrogen production is a transformative approach that retains the core structure of traditional alkaline water electrolysis while utilizing the existing industrial infrastructure. The successful long-term operation of this unit confirms the engineering feasibility and economic viability of this groundbreaking technology. It sets the stage for large-scale applications and opens up new possibilities for harnessing the immense power of seawater in the journey toward a hydrogen-powered future.