All-solid-state lithium batteries, dubbed the "treasure" of next-generation energy storage technology, have long faced a challenging problem: how to maintain close contact between the solid electrolyte and the lithium metal electrode.
A team of Chinese scientists has developed a self-adaptive interphase in an all-solid-state lithium battery that maintains close contact between the lithium metal anode and the solid electrolyte without external pressure, a breakthrough that overcomes a major obstacle to the technology's commercialization.
The findings have been published in the journal Nature Sustainability.
Conventional methods require constant pressure from bulky external equipment, making the batteries too large and heavy for practical use.
Researchers from the Institute of Physics of the Chinese Academy of Sciences (CAS), the Ningbo Institute of Materials Technology and Engineering of CAS, and Huazhong University of Science and Technology found that the contact between the lithium electrode and the solid sulfide electrolyte in an all-solid-state lithium battery is still not ideal, with numerous pores and small cracks forming. These problems not only shorten the battery's lifespan but also pose safety risks.
To address these issues, the team introduced iodide ions into the solid sulfide electrolyte. During battery operation, iodide ions move to the electrode interface under the influence of an electric field and form an iodine-rich interface.
This interface can actively attract lithium ions, automatically filling all gaps and pores, like a self-healing process, thus maintaining close contact between the electrode and the electrolyte.
A prototype battery developed with this technology demonstrated stable and excellent performance even after hundreds of charge-discharge cycles under standard test conditions, far exceeding the level of existing similar batteries.
This technology has the potential to realize future batteries with energy densities exceeding 500 watt-hours per kilogram (Wh/kg), potentially increasing the battery life of electronic devices by at least two orders of magnitude, said Huang Xuejie of the CAS Institute of Physics, one of the corresponding authors of the research paper.
This breakthrough will accelerate the development of high-energy-density all-solid-state lithium batteries, which are expected to play a significant role in humanoid robots, electric aviation, electric vehicles, and other fields, providing safer and more efficient energy solutions, Huang said.
Wang Chunsheng, a solid-state battery expert from the University of Maryland, stated that this research has fundamentally solved a key problem that has hindered the commercialization of all-solid-state lithium batteries, marking an important step towards their practical application.
