CaSino: Could Researchers Hit the Jackpot With Calcium-based Alternative to Li-ion Batteries?
A collaborative battery project, “CaSino,” endeavors to assess the potential use of calcium-sulfur batteries in place of lithium-ion batteries to avoid supply issues.
The Institute of Engineering Thermodynamics at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR, Stuttgart) has announced the continued development of a calcium-based battery that could be used as an alternative to lithium-ion batteries (LiB).
Image used courtesy of the European Battery Alliance
A team of industry partners and research institutions are working as part of the CaSino project to demonstrate the viability of using calcium and sulfur as a sustainable battery energy storage solution.
The Pros and Cons of Lithium-ion Batteries
LiBs are the most common rechargeable battery in use today. They are used in many applications, including laptops, mobile phones, and electric vehicles. LiBs have a high storage capacity and high cell voltage.
Dendrites are a common problem plaguing LiB performance. Dendrites are the thin, finger-like projections that form on the surface of LiBs during repeated charging and discharging. A gradual build-up of these projections can cause short circuits and other performance issues.
Another challenge facing LiB development is the nature of its liquid electrolyte (LE). Research has shown that some organic LEs used in LiBs are highly volatile and flammable. High ambient temperatures can lead to a thermal runaway and even an explosion.
To avoid the possibility of thermal runaway, manufacturers have designed these batteries with several safety features like thermal sensors, temperature monitoring, and safety circuits. These features prevent overcharging and over-discharging, which can cause the battery to heat up excessively.
Despite such efforts, lithium is in limited supply, and researchers have been testing the capabilities of other elements like calcium to provide a solution for keeping up with supply demand.
The Project Consortium
The Institute of Engineering Thermodynamics is one organization among several collaborating under the German Federal Ministry of Education and Research (BMBF)-funded CaSino project, part of the "Battery 2020 Transfer" initiative.
Image used courtesy of fem
Other consortium members include industrial and research organizations like the Karlsruhe Institute of Technology (KIT), the Research Institute for Precious Metals + Metal Chemistry (Forschungsinstitut Edelmetalle + Metallchemie, fem), the Natural and Medical Sciences Institute (NMI), the Institute of Electrochemistry at the University of Ulm, EurA AG (EurA), and IoLiTec Ionic Liquid Technologies GmbH (IoLiTec GmbH).
The project advisory board includes VARTA AG (VARTA), ACCUREC-Recycling GmbH (ACCUREC), Alantum Europe GmbH (Alantum), and CUSTOMCELLS.
The CaSino Battery Project
According to the Institute of Engineering Thermodynamics, calcium is 400 times more abundant than lithium and is much less expensive to source. Unlike lithium, calcium does not form dendrites during battery cycling and is considered safer concerning short-circuiting. Like lithium, calcium has attractive qualities, including a high cell voltage and storage capacity.
Currently, researchers are working past the reactive nature of calcium, which can lead to oxidized surfaces of battery components, blocking ion diffusion. This can cause less than optimum charging and discharging.
Research into the potential to use the calcium-sulfur battery (CaSB) as an alternative to LiBs began in September 2022. Research is pushing further material development to improve CaSB energy density and cycle stability.
KIT has been working on a boron-based electrolyte that could help neutralize this issue. KIT and ionic liquid specialist IoLiTec GmbH are working together to develop KIT’s electrolyte further.
Consortium members are developing other components of the CaSB, including the form and structure of Ca anodes and coatings for enhancing corrosion resistance. The group intends to characterize new materials using morphological and structural analysis methods such as ion and electron microscopy. Computational modeling and simulations will also be conducted alongside ecological and economic assessments of the feasibility of using CaS batteries compared to existing battery technologies.