Calcium Rechargeable Battery Technology

CARBAT is a FET Open research and innovation action in the Horizon 2020 programme and involves 4 European research institutions from different European countries: Institute of Materials Science of Barcelona (ICMAB-CSIC, Spain), Chalmers University of Technology (CHALMERS, Sweden), Complutense University of Madrid (UCM, Spain) and Fraunhofer Institute for Silicon Technology ISIT (Fraunhofer ISIT, Germany).

The project objective is the proof-of-concept of a high energy density battery technology based on calcium. Calcium is the 5th most abundant element in the Earth’s crust, it is non-toxic, and its standard reduction potential is -2.87 vs. SHE (Standard Hydrogen Electrode), very close to that of lithium. Calcium is divalent and hence involve the transfer of two electrons instead of one. Its theoretical capacity is 1.34 Ah/g, significantly higher than the 0.37Ah/g for graphite, used today as anode in Li-ion batteries. Batteries based on Ca metal hold promise of leap-frog increase in energy densities.

CARBAT combines multi-disciplinary scientific efforts and excellence in computational screening, solid-state and coordination chemistry, materials science, electrochemistry and battery engineering, and apply this know-how to:
1. develop novel cathode positive electrode materials operating at suitable potential and having high capacities,
2. optimize electrolyte formulations for fast Ca2+ transport,
3. assembly of full cell demonstrators integrating such materials.

The materials selected via computational screening are afterwards prepared and their electrochemical performance evaluated. Small laboratory cells are built with the most suitable electrolytes developed that are then integrated in larger cell, mimicking industrial formats, and tested. Finally, these were validated and benchmarked vs. the state-of-the-art Li-ion technology using performance and sustainability indicators.