Calcium batteries promise low-cost production and high energy density. However, the electrolytes available so far have not been able to charge calcium batteries at ambient temperature. Researchers at the Karlsruhe Institute of Technology (KIT) have now presented a promising electrolyte class that makes this possible for the first time. If the breakthrough is successful, efficient, large and cost-effective energy storage systems could come within reach, and the comprehensive transition to emission-free mobility and power supply would no longer be a distant vision of the future.
Today's predominant lithium-ion technology cannot fulfil this task on a global scale, says Professor Maximilian Fichtner from KIT, Director of the CELEST research platform (Center for Electrochemical Energy Storage Ulm & Karlsruhe, Germany), which explores calcium batteries and other storage technologies. "Lithium-ion batteries will reach their limits in the medium term due to their performance and some of the raw materials used in them, and could then not be used wherever energy storage would make sense in the context of the energy turnaround.”
One of the most important reasons why lithium-ion technology offers only dim prospects for the future: The earth has only limited reserves of crucial raw materials such as cobalt, nickel and lithium. Fichtner and his team at the Helmholtz Institute Ulm (HIU), which was founded by KIT in cooperation with Ulm University, are therefore focusing on alternative battery technologies. These are based on raw materials that occur much more frequently on earth. He considers calcium to be a promising candidate because it is the fifth most abundant element in the earth's crust. It is also evenly available on earth and has the advantage of being safe, non-toxic and cost effective.
In contrast to lithium, calcium can take up two electrons per atom, which is reflected in a higher current density. At the same time, it delivers a voltage similar to lithium.