Просто хайп? Твердотілі літій-металічні батареї розчарували дослідників
Scientists dispelled expectations about the prospects use of solid-state lithium-metal batteries lithium-lanthanum-zirconium oxide (LLZO) batteries, which were expected to become a promising replacement for traditional lithium-ion batteries.
A study by researchers from Tohoku University notes that the advantages of energy density of lithium-metal batteries garnet-type batteries could be significantly overestimated. According to the results of the analysis, the researchers found that a solid-state lithium-metal battery using an electrolyte based on lithium-lanthanum-zirconium oxide achieves a gravimetric energy density of only 272 Wh/kg, which is only slightly higher than that of modern lithium-ion batteries (250-270 Wh/kg). At the same time, given the high production costs and technical difficulties associated with the manufacture of LLZO, researchers advise paying attention to composite and quasi-solid-state electrolytes as the most practical alternatives.
«All-solid-state lithium-metal batteries have long been considered the future of energy storage, but our results show that LLZO-based designs may not deliver the expected energy density jump Even in the ideal scenario, improvements are marginal, and production and cost problems remain significant», — explains the lead author of the study and a researcher at WPI-AIMR at Tohoku University Eric Jianfeng Cheng.
Solid-state lithium-metal batteries are considered by many to be the most promising technology of the next generation of batteries due to their ability to provide greater safety and energy efficiency. Lithium-lanthanum-zirconium oxide is one of the most well-studied solid electrolytes, with high stability and the ability to conduct lithium ions efficiently.
However, the results of detailed modeling of practical samples based on LLZO have demonstrated that even when using ultra-thin 25-micrometer ceramic separator and high-capacity cathode, battery performance is only slightly superior to the most efficient traditional lithium-ion batteries. One of the key issues in the study, which was the focus of the researchers’ attention, was the density of LLZO, which increases the overall weight and reduces the expected energy benefits. Although the volumetric energy density reaches approximately 823 Wh/L, the additional weight and cost of LLZO hinder its practicality In addition, the fragility of the material, the difficulty of manufacturing thin sheets without defects and problems with lithium dendrites and voids at the edge are also noted.
«LLZO is an excellent material in terms of stability, but its mechanical limitations and weight costs pose serious obstacles to commercialization», — notes Eric Jianfeng Cheng.
As an alternative, the researchers propose to study alternative approaches by combining LLZO with other materials. For example, a promising direction the key to the future of lithium-zirconium oxide is to incorporate lithium-lanthanum-zirconium oxide into polymers that retain high ionic conductivity while increasing flexibility and processability. Another option is quasi-solid-state electrolytes, which require a small amount of liquid electrolyte to improve ionic conductivity and structural integrity.
«Instead of focusing on an all-ceramic solid-state battery, we need to rethink our approach By combining LLZO with polymeric or gel electrolytes, we can improve processability, reduce weight, and still maintain high performance», — says Eric Jianfeng Cheng.
The results of the study were published in Energy Storage Materials
Source: SciTechDaily