Chloride batteries move closer to grid-scale storage project

Seawater covers most of the Earth, and chloride is one of its most available components. That abundance is now attracting interest from battery researchers looking beyond lithium-ion for large-scale energy storage.

An international team working with the Canadian Light Source at the University of Saskatchewan has shown that chloride ions can move far more efficiently through a solid-state battery material. The research involved scientists from Switzerland, Canada and the United States, and focuses on a potential battery pathway better suited to grid storage than phones, laptops or electric vehicles.

The work is still at an early stage, but it speaks to a live issue for the energy sector. Wind and solar generation are expanding, and grids need storage systems that can hold large volumes of electricity over longer periods. Lithium-ion batteries will remain important, but future storage demand is expected to require a wider mix of chemistries, materials and system designs.

For utilities, renewable developers and large energy users, the appeal of chloride is not about chasing a lithium-ion replacement. It is about adding another option to the storage toolbox. Grid-scale batteries place a premium on material availability, cost control, safety, supply security and operating life. Those priorities differ from high-performance consumer and transport applications, where compact size and energy density are often the main drivers.

Lithium supply also remains a strategic concern. Natural Resources Canada data cited in the source material notes that global lithium production has more than doubled over the past five years, while Canada holds 4.4% of known global supplies. Concentrated reserves can create long-term planning risks for major storage projects, particularly as demand continues to rise.

Faster ion movement could unlock new solid-state designs

The central challenge with chloride-ion batteries has been movement. Chloride ions have not historically travelled through solid materials as efficiently as lithium ions, limiting their potential in practical battery systems. For chloride-based batteries to become viable, the ions need a clearer and faster pathway through the solid electrolyte.

Researchers led by Sarbajit Banerjee, professor at ETH Zürich and head of the Laboratory for Battery Science at Switzerland’s Paul Scherrer Institute, worked with PhD student Jingxiang Cheng to modify lanthanum oxychloride, a solid material capable of conducting chloride ions.

The team introduced small amounts of calcium, magnesium or strontium into the material’s atomic structure. Calcium produced the strongest result, helping chloride ions move up to 10,000 times faster. Instead of pushing large ions through a rigid structure, the modified material became more flexible at the atomic level, improving the pathway for ion transport.

The Canadian Light Source helped explain what changed inside the material. Using ultrabright X-rays, including work at the VLS-PGM beamline, the researchers examined how the added elements affected the structure. The findings showed that a more flexible framework can allow chloride ions to move more freely through a solid electrolyte.

The results, published in ACS Applied Energy Materials, add to early research into halide-ion battery systems. Commercial deployment is not around the corner, and chloride-based solid-state batteries will need significant development before they can be tested in real-world grid projects.

Even so, the research is relevant for the business of energy storage. As renewable generation grows, grid operators will need technologies that fit different durations, locations, cost profiles and supply chains. Chloride-based batteries may not be a near-term solution, but they could become part of a broader shift toward storage systems built from more abundant materials.