Scientists at the Hong Kong University of Science and Technology have unveiled a major leap forward in calcium-ion battery technology that could eventually replace lithium-ion batteries for large-scale energy storage — using a material that is orders of magnitude cheaper, more abundant, and more geopolitically accessible than lithium.
Calcium is the fifth most abundant element in Earth's crust. It costs a fraction of lithium per kilogram and is available in large deposits across countries that have no economically significant lithium reserves, including much of Europe, South Asia, and sub-Saharan Africa. Eliminating lithium from energy storage supply chains would address one of the most pressing geopolitical vulnerabilities in the global clean energy transition.
The Engineering Breakthrough
The central challenge that has blocked calcium batteries from competing with lithium for decades is the electrolyte. Calcium ions carry a double positive charge, making them significantly harder to move efficiently through conventional electrolyte materials at room temperature. The HKUST team engineered a novel solid-state electrolyte that allows calcium ions to migrate with low resistance without requiring heating.
In laboratory tests, cells using the new design achieved energy densities competitive with commercial lithium-ion batteries while exhibiting superior thermal stability — a critical safety advantage for large-scale grid installations. The researchers published their results in Nature Energy and said a commercial prototype was achievable within three to five years.