Solid-State Battery Breakthrough News — Hype Or Hope? – CleanTechnica

---

Support CleanTechnica’s work through a Substack subscription or on Stripe.

---

Scientists at the Chinese Academy of Sciences say they have developed a self-healing interface for solid-state batteries that works like a liquid seal. The substance flows to fill in tiny gaps, which keeps the internal layers of the battery tightly joined without the heavy pressure and bulky devices previously required.

“All-solid-state lithium batteries are a promising next-generation energy storage technology due to their use of inorganic solid electrolytes, which improve safety and allow for higher energy density,” Huang Xuejie, corresponding author of the study, told China Daily. The study was published on October 7, 2025, in the journal Nature Sustainability.

What most of us know about solid-state batteries would fit on the head of a pin. Huang explained that in previous solid-state lithium batteries, numerous tiny pores formed at the interface between the anode and electrolyte. These pores accelerated performance degradation and created potential safety risks.

So Huang and his team tried a different approach. Instead of relying on bulky external equipment to maintain pressure on the battery, they developed “dynamically adaptive interphases” through the controlled movement of pre-installed iodide ions in solid electrolytes.

When the battery is in use, the iodide ions migrate toward the anode under the influence of an electric field to form an iodine-rich layer that attracts lithium ions. Those ions fill in the pores, which keeps the anode and electrolyte in close contact even under low external pressure.

Huang said the new design simplifies the manufacturing process and reduces material use without raising production costs. “By adopting this technology, batteries can achieve a specific energy exceeding 500 watt-hours per kilogram, effectively doubling — or even more — the battery life of electronic devices.”

Solid-State Batteries Show Promise

Okay, let’s not get too excited here. This is research that works in the lab, but we all know it is a big leap from the lab to commercially viable production. Even then, manufacturers need to conduct their due diligence to verify the new batteries work as expected in actual use, meaning in the cold and extreme heat, during fast charging, and over long periods of time. Nobody wants another billion-dollar mistake like the one that caused the batteries in first-generation Chevy Bolts to catch fire.

The prototype battery using the new technology has performed well so far in lab tests. It has remained stable and provided exceptional performance even after hundreds of charge/discharge cycles, significantly outperforming comparable batteries, Huang said.

Wang Chunsheng, a professor at the University of Maryland in the United States, said the self-adaptive interphase could “transform the development of all solid state lithium metal batteries by eliminating the traditional reliance on high external pressure for interfacial stability and stable cycling.”

“This strategy also enhances the adaptability of solid state lithium batteries for renewable energy storage, potentially offering efficient and economical solutions to support global sustainable development goals. Moreover, the universal self-adaptive interphase concept could provide a blueprint for the design of next-generation all solid state batteries based on other chemistries, such as sodium or potassium.”

Toyota Solid-State Battery Announcement

Also this week, Toyota announced an agreement with Sumitomo Metal Mining for the mass production of cathode materials for all solid-state batteries for battery electric cars. In a press release, Toyota said that all solid-state batteries are primarily composed of a cathode, anode, and solid electrolyte. The next-generation battery technology the two companies are pursuing will lead the way to smaller batteries with higher output and longer life than the lithium-ion batteries used currently.

The all-solid-state batteries are expected to deliver enhanced performance, longer driving range, shorter charging times, and higher output. Toyota is aiming for a market launch of battery electric cars with all-solid-state batteries by 2028.

Toyota and Sumitomo Metal Mining have been collaborating on cathode material research since 2021, with a focus on challenges such as cathode material degradation during repeated charging and discharging cycles. Using a proprietary powder synthesis technology developed by Sumitomo, the two companies have developed a “highly durable cathode material” that is suitable for solid-state batteries. With over 20 years of experience in supplying cathode materials for a wide range of electric vehicles, Sumitomo Metal Mining will supply the newly developed cathode material and move work toward getting it into mass production.

Together, the companies will work on improving the performance, quality, and safety of cathode materials for solid-state batteries and reducing production costs. They intend to achieve the world’s first practical use of solid-state batteries in battery electric vehicles. If successful, their partnership could change the future of automobiles and help realize a carbon-neutral society.

According to InsideEVs, a third Japanese company will be involved in bringing solid-state batteries to production. The solid electrolyte for the batteries — lithium sulfide — will be supplied by Idemitsu Kosan, one of the country’s largest oil refiners. This electrolyte also plays an important role in giving the new battery its superior properties.

Solid-State Batteries For The Win

The promise of solid-state batteries has been bandied about for decades, but they have been getting closer to production in recent years. Right now, BMW is testing batteries from Colorado company Solid Power as part of its validation and verification process.

Solid Power has adopted sulfides as the pivotal input for its solid electrolyte. Sharp-eyed readers will note that sulfides also figure prominently in the Toyota/Sumitomo venture. In addition to pushing volatile liquids out of the picture, the sulfide material eliminates the polymer separator typical of lithium-ion batteries.

“Solid Power’s sulfide-based solid electrolyte is the key ingredient that powers Solid Power’s All-Solid-State Battery Platform technology,” the company has said. “This thin, solid layer acts as a barrier to keep the anode and cathode from touching one another, which would short the battery. It also acts as a conductive electrolyte.”

Honda is also hot on the trail of solid-state batteries. Earlier this year, it opened a 27,000 square meter (300,000 square foot) demonstration production line for solid-state battery cells at its R&D center in Sakura City, Japan. The machinery at the new testing factory allows Honda engineers to test and verify every process in the production of a battery cell, including:

• weighing electrode materials, and mixing them in the correct proportions
• coating the rolls of electrode film
• assembling the two electrode (anode and cathode) and solid electrolyte to form a cell
• assembling cells into modules.

The new facility will permit rapid testing of different factors affecting the design and production of the final cells, particularly material specifications and manufacturing processes.

Today’s batteries, as good as they are, still fall far short of good old gasoline — or Jet A — in terms of energy density measured either by weight or volume. Solid-state batteries could go a long way toward narrowing that gap.