Energy Management Core Problem of Solid-State Batteries Solved

Related Vendors

FAULHABER Drive Systems

Wuxi InfiMotion Technology Co., Ltd.

Another technological advancement in high-performance solid-state batteries has been reported from China: A kind of "liquid seal" can effectively close tiny cracks and pores, ensuring that the contact within the batteries remains permanently stable—without the need for a pressure device.

Chinese materials scientists have achieved another technological breakthrough on the path to high-performance solid-state batteries: they have developed a novel "self-healing interface" that ensures the necessary contact between the lithium-metal anode and the solid electrolyte in such batteries without the currently required high pressure, the researchers write in a paper published in the American journal "Nature Sustainability."

Self-Healing Effect for Cracks And Pores

Their invention acts like a kind of "liquid seal," effectively sealing tiny cracks and pores in solid-state batteries, write the scientists, who work at the Physics Institute of the Chinese Academy of Sciences (CAS), the "Ningbo Institute of Materials Technology and Engineering" (also CAS), as well as the "Huazhong University of Science and Technology."

With their new material, the contact in the batteries remains permanently stable, without the need for bulky pressure devices. Once this technology is production-ready, experts believe it could eliminate a bottleneck for the mass production of high-performance "solid-state" batteries.

The concept of the new interface is described as "dynamically adaptive." To achieve this, a sulfide solid electrolyte is doped with mobile iodide ions. Under voltage, the iodide ions migrate to the anode and form a thin, iodide-rich interlayer there. This attracts lithium ions, automatically filling all unwanted voids—a "self-healing" effect for cracks and pores.

The battery life of electronic devices is expected to at least double. This will accelerate the development of all-solid-state lithium batteries with high energy density.

Professor Huang Xuejie

Powerful Even After Hundreds of Charge Cycles

In initial prototypes, the performance of the test cells reportedly remained stable even after hundreds of charge and discharge cycles. A cell retained 90.7 percent of its initial capacity after 2,400 cycles, according to the website of the CAS Institute of Physics. Even a pouch cell maintained 74.4 percent of its capacity over 300 cycles without external pressure.

According to Huang Xuejie, one of the authors of the paper, energy densities of more than 225 Wh/lb are achievable with this method. The design of the innovative battery type is also relatively simple, with reduced material requirements and improved durability compared to current solid-state batteries.

"The battery life of electronic devices is expected to at least double. This will accelerate the development of all-solid-state lithium batteries with high energy density," Professor Huang is quoted as saying by the Chinese science newspaper Keji Ribao.

Suitable for Safety-Critical Applications

The new technology not only makes the novel batteries more powerful but also safer, it was further stated. This makes them ideal for applications "in humanoid robots, electric aviation, electric cars, and many other fields," according to Huang.

The new self-healing layer represents a "paradigm shift in interface design," commented Wang Chunsheng, another renowned battery researcher from the University of Maryland, on his colleagues’ paper in Nature Sustainability.

The infamous "contact loss problem" in the battery industry is solved without complex external mechanical systems. This makes the production of high-performance and "truly practical solid-state batteries" much more realistic, wrote Wang.

Solution Sought Since the 1970s

Worldwide, intensive research is being conducted on new solid-state batteries, which are currently considered the "Holy Grail" of energy storage due to their higher energy density. The solid-solid contact has so far remained one of the biggest practical problems. During charging, the rigid layers often separate from each other, interrupting the flow of electricity.

Since the 1970s, a solution has been sought, but it was only modern materials in the 2010s that gave a boost to the field of research.

Without the adaptive interlayer, solid-state cells currently need to be held together with over five megapascals of external pressure (around 50 atmospheres). This makes them relatively heavy and impractical.

Ready for Series Production in Three to Five Years

Before the technology becomes ready for series production, there are still many detailed problems to solve, as always. It could take another three to five years until all the necessary manufacturing processes and equipment are developed, according to the researchers.

In principle, however, the new method is not limited to lithium ions alone. The Chinese scientists mention bromide or chloride ions as potential alternatives, which could be useful in the development of sodium or potassium solid-state cells.

Despite the remaining optimization tasks, the invention is currently being celebrated in Chinese specialist circles as a significant milestone toward market readiness for very powerful solid-state batteries. The paper from the American scientific journal is actively shared on the WeChat accounts of many Chinese battery scientists and is accompanied by enthusiastic comments.

Henrik Bork, longtime China correspondent for the Süddeutsche Zeitung (German daily newspaper) and the Frankfurter Rundschau (German daily newspaper), is Managing Director at Asia Waypoint, a consultancy specializing in China and based in Beijing.

Future-Proof Authentication with Universal RFID Readers

Universal RFID Readers: One Solution for All Credentials