From pebbles to power: the rise of potassium silicate batteries

In our most recent episode of Lexicon, we interviewed Dr. Mohamad Khoshkalam, a postdoctoral materials scientist at the Technical University of Denmark.

In this episode, we discovered how potassium silicate , an abundant earth material, is being transformed into a sustainable alternative to lithium-ion batteries. This could offer potential breakthroughs in performance and safety. Let’s find out how.

Lithium-ion batteries aren’t all that

Lithium-ion batteries have become the standard for energy storage in electric vehicles (EVs) and many other applications worldwide. Despite this, they have significant issues. Lithium is relatively rare and expensive as a raw material, and its extraction is environmentally harmful.

However, there are additional concerns. For instance, lithium-ion batteries present safety risks, particularly if they overheat and ignite. As the demand for electric vehicles and renewable energy storage increases, so will the need for these batteries.

To overcome these obstacles, Dr. Khoshkalam and his colleagues are creating a different battery that uses potassium silicate, a plentiful and safe environmental resource. “Our patent is on developing a new class of solid-state electrolytes. In terms of chemical composition, they’re very similar to feldspar and simple crystallites,” Dr. Khoshkalam explained.

As the raw materials can readily be found in common rocks and pebbles, they potentially offer a sustainable and cost-effective solution for energy storage.

The promise of solid-state batteries (SSB)

Solid-state batteries differ from traditional lithium-ion batteries in that they use a solid electrolyte instead of a liquid one. Because of this, they provide several benefits, such as improved safety, higher energy density, and potentially quicker charging times.

“In terms of ionic conductivity, they’re very similar to solid-state lithium-based electrolytes,” Dr. Khoshkalam noted. “When it comes to energy density, it’s very similar, and in terms of charging speed, it’s a little bit lower, but we have new solutions that can reach the same level as lithium batteries.”

Another major benefit of potassium silicate-based batteries compared to lithium-ion is their safety. Unlike lithium-ion batteries containing flammable liquid electrolytes, potassium silicate batteries are much less likely to catch fire.

“It’s significantly safer and more environmentally friendly because we don’t use toxic materials like cobalt or nickel, which are associated with hazardous mining and human rights violations,” Dr. Khoshkalam added.

Overcoming challenges in SSB development

Yet, for all the advantages of potassium silicate-based batteries, significant challenges remain before they can be commercialized. Like most new technologies, one of the main issues is the technology’s scalability.

SSBs, in general, are difficult to manufacture on a large scale due to the fragile nature of the ceramic layers used in the electrolyte. “One of the biggest challenges of solid-state batteries, in general, is the fragile nature of ceramic layers… We’re working on solutions to keep these layers together using low pressure, similar to what is used in lithium-ion batteries,” Dr. Khoshkalam explained.

However, there is a slight problem with potassium silicate SSBs on the atomic scale. Potassium ions are larger and heavier than lithium, which can slow their movement through the electrolyte and reduce the battery’s performance. Thankfully, Dr. Khoshkalam’s team has found innovative ways to overcome this issue.

“The first thing we did to make it faster is removing elements from the structure… We made it more hollow, so we allow these things to pass,” he said. He explained that modifying the electrolyte’s structure has achieved conductivity levels comparable to lithium-ion batteries.

Environmental and ethical benefits

As mentioned earlier, potassium silicate-based batteries offer significant environmental and ethical benefits. The raw materials used in these batteries are abundant and non-toxic, which reduces the environmental impact of mining and manufacturing.

For example, potassium silicate does not rely on cobalt, a material often associated with unethical mining practices, including child labor. “It’s significantly safer and more environmentally friendly because we don’t use toxic materials like cobalt or nickel, which are associated with hazardous mining and human rights violations,” Dr. Khoshkalam emphasized.

Using earth-abundant materials also contributes to the sustainability of potassium silicate batteries. Unlike lithium, concentrated in specific regions, potassium, and silicon are found widely across the Earth’s crust.

This abundance means that the supply chain for potassium silicate batteries would be more stable and less susceptible to geopolitical issues. Given recent conflicts and global tensions, this is a major consideration.

“We didn’t use any elements in the European Union critical elements list… That’s strategically also important, both in terms of price sustainability and also you’re not going to be affected by geopolitical issues,” Dr. Khoshkalam noted.

The path to commercialization

Despite the challenges, Dr. Khoshkalam is optimistic about the future of potassium silicate batteries. His team is developing a prototype to demonstrate the technology’s viability to potential investors and industry partners.

“I think it can be manageable in a span of three to four years to reach something like TRL4,” he said. TRL4 refers to level four of the Technology Readiness Level, a scale used to assess the maturity of a technology. While the technology may take up to 10 years to fully commercialize, the team is committed to overcoming the obstacles.

In the meantime, Dr. Khoshkalam sees opportunities for using potassium silicate batteries in specific applications where their unique properties provide advantages. For example, they could be used in grid-scale energy storage systems, where their safety and cost benefits would be precious.

“Having this cheap solution that captures excess energy—like from wind turbines producing more energy than can be stored—could help make cheaper charging stations and support the electrification of transportation,” he suggested.

Why choose?

Despite his excitement about the technology, Dr. Khoshkalam is realistic about the challenges ahead. For example, he recognizes that potassium silicate batteries may only partially replace lithium-ion batteries in some applications.

As he explained to IE , he envisions them as a complementary technology that can coexist with other types of batteries, providing a more sustainable and cost-effective option where it makes sense.

“We’re not trying to make a deficient product, but even halfway there could have a big impact, considering the materials we’re using—nothing, just earth-abundant silicates,” he said.

Dr. Mohamad Khoshkalam and his team’s work represents a significant step in developing sustainable battery technology. By harnessing the potential of potassium silicate, they are creating a new class of batteries that could play a crucial role in transitioning to a greener, more sustainable energy future.