Breakthrough Calcium-Ion Battery Could Rival Lithium for Sustainable Energy

A team of researchers at The Hong Kong University of Science and Technology (HKUST) has made a breakthrough in battery technology. They developed a new calcium-ion battery (CIB) system using quasi-solid-state electrolytes (QSSEs). This innovation could offer a more sustainable alternative to traditional lithium-ion batteries.

The project was led by Professor Yoonseob Kim from HKUST's Department of Chemical and Biological Engineering. The team's findings, published in the journal Advanced Science, highlight the battery's strong performance. It achieved a reversible specific capacity of 155.9 mAh g−1 at 0.15 A g−1 and retained 74.6% of its capacity after 1,000 cycles at 1 A g−1.

The QSSEs in the system demonstrated high ionic conductivity—0.46 mS cm−1—and a calcium-ion transport capability above 0.53 at room temperature. These improvements address past challenges with cation transport and stability in CIBs.

Calcium-ion batteries have long been seen as a promising option due to their use of abundant materials and wide electrochemical window. However, earlier versions struggled with efficiency and consistency. This new design could change that, making CIBs a viable competitor to lithium-ion technology.

The global push for sustainable energy has increased demand for better battery solutions. If scaled successfully, this system might transform energy storage in renewable power and electric vehicles.

The research marks a significant step forward for calcium-ion battery technology. Strong partnerships between academia and industry will be key to moving this innovation from labs to real-world use. No official timeline for commercialisation has been announced as of February 2026.