Recently, a team led by Researcher Huang Xuejie from the Institute of Physics, Chinese Academy of Sciences / Beijing National Laboratory for Condensed Matter Physics, collaborating with a team led by Professor Zhang Heng from Huazhong University of Science and Technology and a team led by Researcher Yao Xiayin from the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, has developed an anion regulation technique, breaking through the major bottleneck hindering the practical application of all-solid-state batteries. The related research results were published in Nature Sustainability.
All-solid-state lithium metal batteries are hailed as the “holy grail” of next-generation energy storage technology, but they have long faced a thorny problem – solid electrolyte and the lithium metal electrode must maintain tight contact. The traditional approach relies on bulky external equipment to apply continuous pressure, resulting in batteries that are too large and heavy for practical use.
In this study, the research team identified the crux of the problem: the contact between the lithium electrode and the electrolyte in all-solid-state lithium metal batteries is not ideal, containing numerous microscopic pores and cracks.
To solve this problem, the research team introduced iodide ions into the sulfide electrolyte. During battery operation, these iodide ions move to the electrode interface under the influence of the electric field, forming an iodine-rich interface layer. This layer can actively attract lithium ions, automatically filling all gaps and pores like “self-healing,” thereby keeping the electrode and electrolyte tightly bonded at all times. This eliminates the dependence on external pressure for maintaining interface contact in all-solid-state lithium batteries.
More importantly, a prototype battery prepared based on this technology demonstrated stable and excellent performance even after hundreds of charge-discharge cycles under standard testing conditions, far exceeding the level of existing similar batteries.
Professor Wang Chunsheng from the University of Maryland, USA, a solid-state battery expert, commented that traditional techniques require applying external force exceeding 5 Megapascals, equivalent to 50 atmospheres, to maintain interface stability, whereas this new technology fundamentally changes this predicament, taking a decisive step towards practical application.
Huang Xuejie stated that this new design not only simplifies the manufacturing of all-solid-state lithium batteries and reduces material usage but also makes the batteries more durable. “Using this technology, batteries with an energy density exceeding 500 Watt-hours per kilogram can be produced. The endurance of electronic devices is expected to increase by more than twofold. This will accelerate the development of high-energy-density all-solid-state lithium metal batteries, which are expected to play significant roles in humanoid robots, electric aviation, electric vehicles, and other fields in the future, offering safer and more efficient energy solutions.”
However, Huang Xuejie pointed out that future challenges will focus on process and equipment development, and mass production is estimated to still require 3 to 5 years.
Source: China Science Daily
