Next Generation All-Solid-State Batteries Promise Better EV Range and More

If you are among the millions of people who suffer from “range anxiety,” help is on the way.

Range anxiety, in case you haven’t experienced it, is the fear that your electric vehicle won’t have enough battery power to reach your intended destination, leaving you stranded. It’s what can turn an otherwise pleasant trip from San Francisco to Los Angeles into a battle against chemistry and physics.

So, what form will this relief take? Why will drivers soon complete that drive down the California coast with ions to spare?

In a system as complex as an automobile, there’s no single answer. Incremental advances affecting range can be found everywhere – from software refinements to weight reductions to improved aerodynamics. But the biggest game changer will come from improvements in battery technology. And one of the most consequential advances is the dawning of the all-solid-state battery or, as it’s known, the ASSB.

The next leap for EV batteries

To understand why ASSBs hold so much promise, it’s useful to contrast them with the technology it’s expected they’ll one day replace: lithium-ion batteries.

To their credit, lithium-ion batteries have been the mainstay technology powering everything from cell phones to laptops to EVs. And to be sure, they have been instrumental in creating a mass market for devices and electric vehicles. Indeed, according to a 2023 report by the International Energy Agency, EV sales rose to 14% of all new cars sold in 2022. That’s up from 9% the prior year. By 2030, they’re expected to reach 35% of all new cars sold.[i]

Given this growth trajectory, manufacturers are understandably enthusiastic about the potential benefits of ASSBs. One such benefit can be found in the name itself. Specifically, the word “solid”. Whereas lithium-ion batteries generate energy through chemical reactions occurring in a liquid electrolyte solution, ASSB’s replace that liquid with a solid electrolyte, usually consisting of ceramic or metal.

Progress where it matters most

Transitioning from liquid to solid holds the promise of significant improvement in what matters most when it comes to batteries. Namely, energy density or the amount of energy that can be stored within a given volume of space.

In the case of automobiles, integrating more energy-dense ASSB’s would mean considerably more energy could be stored in the volume currently allocated to batteries, thus extending the range with little increase in vehicle size or weight. And in devices where space and/or weight are at a premium, ASSBs could allow for smaller or lighter devices.

Achieving conductivity in a solid electrolyte has been a key barrier to commercialization, but researchers worldwide have been making steady progress thanks to sizeable investments from companies and partnerships between industry and science.

Beyond energy density

As well as improved energy density ASSBs, because of their solid state, can’t be spilled and don’t leak, which gives them greater stability. Furthermore, the electrolytes used in ASSB’s are generally not flammable, reducing the likelihood of fires or explosions.

These benefits make ASSB’s a natural for EVs, where improved stability and low flammability help mitigate key dangers inherent in putting complex energy systems in motion.

Longevity and duration gains

And while ASSB’s will extend range with greater safety, like all batteries, they’ll require re-charging. All-solid-state technology offers improvements in both charging times and battery durability.

These Improvements are a direct result of the enhanced conductivity properties of solid-state materials, which allow the ionic switches to be flipped more quickly. By some estimates, solid-state batteries will be able to reach an 80% charge in about 15 minutes.

Repeated charging takes a toll, however, as switching states strain the ions, causing batteries to degrade over time. However, that fall-off happens more gradually for ASSB’s, lengthening their useful life nearly five-fold over lithium-ion batteries.

When will we see them?

Given their advantages, you’d expect to see ASSB’s every time you pop the hood (or, more accurately, pull up the floorboards) on your EV or get a glimpse inside your tablet. But although the technology itself is proven, companies haven’t yet cracked the code on producing ASSBs at scale.

Still, among those making progress on changing that is SK Group’s SK On, which has spurred a series of groundbreaking ASSB research. The company is developing two types of ASSBs. One uses polymer-oxide composites whose greater conductivity ensures faster charging times. SK On is also developing sulfide-based solid-state batteries, whose high energy density increases the range of EVs.

In the U.S., SK On has also partnered with Solid Power, a leader in developing all-solid-state batteries. Together, the two companies plan to validate that Solid Power’s all-solid-state-cells can be manufactured on existing lithium-ion battery manufacturing equipment. SK On’s goal is to produce early-stage prototypes of polymer-oxide-based solid-state batteries and sulfide-based solid-state batteries in 2026 and commercialize them in 2028.

With their increased range, and improved safety and durability, ASSBs do more than combat range anxiety. They represent a significant leap forward on many fronts, making EVs a viable option for more consumers in a world hungering for cleaner transportation alternatives.