12.10.2023
Source: Energy & Management Powernews
A research consortium with the participation of the TU Berlin is developing a zinc-hydrogen battery. It is much cheaper to produce than a lithium-ion battery.
The novel zinc-hydrogen battery can not only store electricity with high efficiency, but also releases hydrogen in addition to electrical energy when discharging. This is achieved by combining the negative zinc electrode of the battery with the principle of alkaline water electrolysis. A special hydrogen/oxygen gas electrode is used as the positive counter-electrode, which serves as an electrocatalyst.
Initial tests of the new energy storage device showed an efficiency of 50 percent for electricity storage and 80 percent for hydrogen generation, with a projected lifetime of ten years, according to TU Berlin.
On the storage options for electricity, which are becoming increasingly important for the energy transition in Germany, Prof. Dr. Peter Strasser, head of the "Electrochemical Catalysis, Energy and Materials Sciences" department at TU Berlin, explains, "In the public perception, battery and hydrogen technologies have been in competition with each other until now. The new approach of our consortium project shows that it is worth challenging this way of thinking and instead picking the best of both worlds."
Wide field of application
According to Strasser, the heart of the new combi-battery is a catalytically active, bifunctional gas electrode. Together with the negative zinc electrode, it is located in a liquid electrolyte of potassium hydroxide and water, i.e. caustic potash solution. During the discharge process, the catalyst of the gas electrode splits off hydrogen molecules from the water molecules. This hydrogen escapes and can be stored and reused. At the same time, electrically negative OH ions in the electrolyte migrate to the zinc electrode. There they react with the zinc to form zinc oxide and water, releasing electrons. This discharge process thus simultaneously supplies usable electrical energy and hydrogen gas.
"The hydrogen can either be used directly as a raw material in chemical industry processes, converted into electricity in conventional fuel cells or turbines, or used as a fuel for heat in gas-fired power plants or district heating networks," says Strasser, explaining the range of applications. Compared with conventional lithium-ion batteries, the new battery uses only much cheaper raw materials (steel, zinc, potassium hydroxide, water), which are only about one-tenth as expensive. They also make the battery easily recyclable.
Building a demonstrator by the end of 2023
The TU Berlin researchers now plan to build a demonstrator and conduct reliability tests by the end of the year. The charging and discharging parameters are to be optimized in such a way that stable operation is possible over several thousand cycles. Through the company "Zn2H2 GmbH", which is also involved in the consortium and has already applied for several patents on the process, a rapid implementation in the market would be ensured, according to the TU.
The other consortium partners in the project are Steel PRO Maschinenbau GmbH, the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research (IFAM) and the Fritz Haber Institute of the Max Planck Society.
Author: Günter Drewnitzky
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