Researchers from the University of Science and Technology of China (USTC) claimed to have developed a new material, lithium zirconium chloride (LZC), which could help lower solid-state lithium batteries’ production costs.

The findings have been published in the science journal Nature Communications.

Solid electrolytes are essential to produce safe, energy-dense all-solid-state lithium batteries. Among different solid electrolytes, the chloride solid electrolytes were recently found to exhibit the desirable characteristics of both sulfide and oxide systems, like high ionic conductivity, oxidative stability, and deformability. These desirable characteristics rapidly increased the broad interest in chloride solid electrolytes. However, the major hurdles that hinder the mass production of solid electrolytes are the cost of raw materials and low humidity tolerance, noted the researchers.

The team designed and synthesized the material with all the advantages of chloride solid electrolytes well preserved. LZC is stable in an atmosphere with 5% relative humidity, unlike sulfide solid electrolytes, thus bypassing the strict conditions required during synthesis and storage.

Commenting on the advantages of LZC in the mass production of solid-state lithium batteries, Prof. MA said that the advantages in mass production were achieved without sacrificing any of the attractive characteristics of chloride solid electrolytes.

The raw material cost of LZC is way below the $10/m² threshold for ensuring the cost competitiveness of all-solid-state batteries. At only $1.38/m² for 50 μm thickness, this is much lower than that of even the cheapest chloride system at $23.05/m².

LZC still possesses high ionic conductivity (0.81 mS cm-1), outstanding deformability, and remarkable compatibility with 4V-class cathodes. A cell with a LiNi0.8Mn0.1Co0.1O2 cathode and an LZC solid electrolyte delivered a stable specific capacity of about 150 mAh g-1 after 200 cycles at 200 mA g-1 without considerable fade, competing even with the best among similar all-solid-state cells.

“All-solid-state lithium batteries play an important role in achieving the goal of ‘peak carbon dioxide emissions’ and ‘carbon neutrality,” Prof. MA stated. “The achievement of both cost-effectiveness and high performance of Li₂ZrCl₆ remove a major obstacle to the commercialization of such batteries.”

To create more efficient and affordable all-solid-state batteries, the team will experiment with other 4+ cations, denoted as M, to synthesize Li₂MCl₆ solid electrolytes.

Researchers globally are pushing the limits to achieve greater energy densities.

Recently, researchers from Chalmers University of Technology, Sweden, published a paper outlining a new concept for rechargeable batteries made of cement. Developed by scientists attached to the varsity’s Department of Architecture and Civil Engineering, the concept involves a high-rise concrete structure capable of storing energy like a giant battery. The concept involves a cement-based mixture mixed with small amounts of short carbon fibers.

Earlier this year, researchers from the Massachusetts Institute of Technology and other organizations found a novel electrolyte that could allow lithium-ion batteries to store about 420 watt-hours per kilogram. Such batteries can now typically store about 260 watt-hours per kilogram of energy.