New ‘Rock’ Battery Tech: A Future Alternative to Lithium-Ion?

A decade from now, solid-state batteries derived from plentiful rock silicates could provide an eco-friendly, efficient, and safer alternative to the prevalent lithium-ion batteries in electric vehicles (EVs). It sounds like a stoner’s dream—but it’s real: Researchers at the Technical University of Denmark (DTU) have patented a groundbreaking superionic material based on potassium silicate, a mineral that can be extracted from ordinary rocks.

Derived from the very rocks that cover 90% of Earth's surface, this breakthrough could overcome many of the environmental and logistical challenges associated with current battery technologies.

Lithium’s limitations

Lithium-ion batteries, although widely used, have significant limitations, including safety concerns, high costs, and environmental impact. Extracting lithium involves either hard rock mining or evaporating brine, both of which can lead to substantial ecological disruption. Hard rock mining consumes large amounts of water and energy, causing deforestation and soil degradation. Brine extraction depletes local water resources, affecting communities and ecosystems. Additionally, recycling lithium-ion batteries is complex and costly, with improper disposal risking toxic substance release. Given these challenges, the need for lithium-free batteries is pressing.

Potassium silicate’s potential

"The potential of potassium silicate as a solid-state electrolyte has been known for a long time, but in my opinion has been ignored due to challenges with the weight and size of the potassium ions," stated DTU researcher Mohamad Khoshkalam. Despite these challenges, Khoshkalam and his team are optimistic. "The first measurement with a battery component revealed that the material has a very good conductivity as a solid-state electrolyte."

DTU researcher Mohamad Khoshkalam has invented a new material based on rock silicates for a solid-state electrolyte that has the potential to replace lithium in future electric car batteries. DTU/FRIDA GREGERSEN

Khoshkalam emphasized, "We have shown that we can find a material for a solid-state electrolyte that is cheap, efficient, eco-friendly, and scalable—and that even performs better than solid-state lithium-based electrolytes." The patented potassium silicate material boasts numerous advantages, such as insensitivity to air and humidity, ease of production in open environments, and operation at near room temperature. This will facilitate safer and more economical battery production.

Challenges and next steps

Transitioning from laboratory success to commercial application presents challenges. The technology readiness level of potassium and sodium silicate batteries remains low, and substantial development is needed before these batteries can be mass-produced and used in EVs. The material must maintain its integrity through the complex manufacturing processes required for EV batteries. Currently, the ultra-thin layers used in these batteries are pressed together at high pressure in the lab, a method not easily replicable on an industrial scale.

Khoshkalam's next objective is to develop a demonstration battery to showcase the material's potential to companies and investors. A prototype is expected within 1–2 years, paving the way for further advancements and eventual market introduction.

DTU's innovative research on potassium silicate-based solid-state batteries heralds a potential paradigm shift in EV battery technology, offering a more sustainable and efficient alternative to lithium-ion batteries. This breakthrough could overcome many of the environmental and logistical challenges associated with current battery technologies. However, significant research and development efforts are still required to bring this technology from the lab to the road.