Lithium to solid-state: What will this EV evolution bring?

There are three key factors encouraging developers to figure out what the next generation of electric vehicle (EV) power will look like. One is range, another cost, and the final one is supply. 

The industry has been kept under tight reins as these factors have been held over its head for quite some time. EV range is slowly increasing, but there are promises of further growth there. In terms of cost, lithium-ion batteries just aren’t able to keep up with demand, which is also a result of the last point—the limited supply of lithium for automotive use.

In the ever-evolving world of EVs, the race to develop more efficient, long-lasting, and safer batteries is a priority. The transition from liquid electrolytes in lithium-ion batteries to solid-state batteries (SSBs) is hailed as a potential game-changer. However, as the switch to SSBs seems imminent, industries are most likely hopeful for, yet vigilant of, change. 

Understanding solid-state batteries

Commenting on this is one of the leading companies in the battery technology space. Choi Kyoung-hwan, Head of SK On Next Generation Battery R&D Office—and leading figure in the battery industry—helped us dive deeper into the progress and potential of SSBs as a solution to a number of electrification concerns for businesses and the everyday driver.

Kyoung-hwan paints an optimistic picture, noting, "The battery industry is advancing the development of all-solid-state technology, which is gaining significant attention as the next-generation battery." With SK On's recent announcement of a new oxide-based solid electrolyte with excellent lithium-ion conductivity, the horizon looks promising. "We expect that this breakthrough will expedite the commercialisation of all-solid-state batteries," adds Kyoung-hwan. 

The company is also working on two distinct types of SSBs: high molecular/oxide-based and the sulphide-based. SK On aims to introduce early-stage prototypes by 2026 and expects to commercialise them by 2028.

Benefits of solid-state batteries in EVs

What makes solid-state batteries the next big thing for EVs? Kyoung-hwan succinctly puts it, "The potential gain is widespread EV adoption." Given their reputation for stability and efficiency, SSBs are well-positioned to promote EV adoption and strengthen automakers' EV portfolios.

The impact of lithium production drives SSB research

Aside from the technical advancements found in SSBs, there is more to the conversation in terms of sustainability. According to the International Energy Agency (IEA), shortages of lithium and cobalt could occur as early as 2025. Currently, the average electric car uses eight kilogrammes of lithium and, with a feasible 22 million tonnes of lithium, around 2.8 million cars can be produced—not to mention the impacts on the industry if it were to be the sole solution for EV batteries. 

Much like the energy mix, automotive requires a multifaceted approach, which is where the idea of the SSB comes into play. There is also the option to deliver sodium-ion batteries (SIBs)—basically ‘salt batteries’—as another option.

The challenges ahead of SSB research and development

Despite their promising potential, solid-state batteries aren't without challenges. The most evident hurdle, as Kyoung-hwan mentions, is their high cost. "Major oxide-based solid electrolytes currently command prices of around US$1,000 per kilogram, while sulphide-based solid electrolytes are priced at approximately US$2,000," he says. However, he is hopeful, believing that "the industry is planning to enhance cost competitiveness through mass production and technological advancements."

Furthermore, Kyoung-hwan flags a significant safety concern with sulphide solid electrolytes. They can produce toxic hydrogen sulphide gas upon reacting with atmospheric moisture. "This issue is expected to be resolved by manufacturing batteries under moisture-free conditions or by developing materials that minimise moisture-related reactions when exposed to air," Kyoung-hwan assures.

Solid-state batteries are indeed seen as the silver bullet of electrification. But, Kyoung-hwan also cautions about the risks associated with them. While they offer better capacity than lithium-ion batteries, their successful entry into the EV market hinges on price competitiveness. 

Moreover, if lithium-ion battery technology continues its upward trajectory in terms of safety enhancements, the advantages of SSBs might potentially be overshadowed.

The future of EVs is exciting, with innovations like solid-state batteries promising to redefine the landscape by enabling greater efficiencies and less environmental strain. However, as Kyoung-hwan's insights suggest, challenges lie ahead. Collaboration, innovation, and a focus on sustainable solutions will be key in driving the future of electrification.