Recently, a new solid electrolyte material for lithium batteries, lithium zirconium chloride, was introduced, which successfully reduced the cost of raw materials with a thickness of 50 microns to $1.38 per square meter, while the corresponding cost of the cheapest chloride solid electrolyte before was $23.05 per square meter. This new material was designed and synthesized by Ma Cheng, a professor of the University of Science and Technology of China. This material overcomes the bottleneck that it is difficult to have both the production cost and the comprehensive performance of solid electrolyte materials for lithium batteries. It is expected to promote the commercialization process of all solid lithium batteries that are safe and have more room for energy density improvement. Relevant achievements were published in Nature Communication on July 20.

It is worth noting that on the second day after the release of this achievement, the lithium battery sector was "booming", with the red stock accounting for 87%, and 19 "lithium battery" stocks of A-share hit a new record. Investors believe that this heavy progress may be one of the drivers of the "lithium battery" sector, and the market is also full of expectations for this "high-quality and cheap" new material.

The discovery of lithium zirconium chloride makes the chloride solid electrolyte have the advantages of both performance and cost.
You can have it both ways
At present, spontaneous combustion and explosion accidents of traditional commercial lithium batteries occur frequently. Not long ago, the self ignition accident of electric vehicles in Hangzhou was still frightening. "The traditional commercial lithium ion battery using organic liquid electrolyte has the advantages of small size, large capacity, long service life, etc., but it is easy to catch fire and even cause explosion after its thermal runaway." Ma Cheng told the China Science Daily that the solid electrolyte in the solid lithium battery can eliminate the "flammable and explosive" and leakage problems caused by the liquid electrolyte, and achieve safe energy storage.
Solid state electrolyte is the core component of solid state lithium battery, but its production cost and comprehensive performance can not meet the commercial needs. "Although solid lithium batteries have higher safety, the cost of solid electrolyte raw materials is very high, and a large number of solid electrolytes with good performance have poor stability to humidity. They need to be prepared and stored in an environment where the dew point does not exceed minus 40 degrees Celsius, which greatly increases the production cost." Ma Cheng said frankly that all these have brought great challenges to the commercialization of all solid state batteries. For production cost and comprehensive performance, can we have both? The new chloride solid electrolyte material, lithium zirconium chloride, designed and synthesized by Ma Cheng's team, has successfully reduced the cost of raw materials with a thickness of 50 microns to $1.38 per square meter, far below the threshold of $10 per square meter to ensure the competitiveness of all solid state batteries in the market. In addition, lithium zirconium chloride can remain stable in a relatively humid atmosphere with a dew point up to minus 15 degrees Celsius. Its synthesis and storage are not demanding on the environment and are relatively easy to prepare, which further reduces production costs.
It is worth noting that the reduction of production costs does not come at the expense of performance.
"The biggest highlight of this new achievement is that the materials we designed still have strong competitiveness in comprehensive performance while significantly reducing the cost of large-scale production." Ma Cheng said that in terms of ionic conductivity, deformability and compatibility with high-voltage positive electrodes, lithium zirconium chloride well integrates the advantages of sulfide and oxide solid electrolytes. The cycle performance of all solid state battery composed of high nickel ternary positive electrode can even be comparable to that of lithium ion battery based on liquid electrolyte.
New materials are not perfect
Current mainstream power batteries, whether lithium iron phosphate batteries or ternary lithium ion batteries, are all lithium ion batteries with liquid electrolyte. In addition to the disadvantages of "flammable and explosive", the energy density has basically reached the "ceiling". Ma Cheng believes that in the field of new energy electric vehicles, all solid state lithium batteries may be the ultimate solution to safety problems and will become a subverter in the lithium battery industry. In addition, all solid state batteries can use higher energy anode and cathode materials, and the battery structure can also provide more possibilities for "brain hole opening". However, although the all solid state lithium battery is generally favored by the scientific and industrial circles, its commercial mass production still faces many obstacles, such as the need to find more suitable solid electrolyte materials for mass production, and the need to make the solid electrolyte film thinner. Ma Cheng said frankly that only when the solid electrolyte materials give consideration to both cost and performance, and have great advantages, can they fully replace the liquid electrolyte. In addition, the solid electrolyte membrane is mainly used to transport lithium ions, with a thickness of 10-40 microns, which makes it competitive in terms of energy density. These major obstacles cannot be removed overnight. Lithium zirconium chloride is the first high-performance chloride solid electrolyte based on tetravalent cations. Ma Cheng said that it has overcome the major bottleneck that it is difficult to have both production cost and comprehensive performance, and has significant advantages in both aspects. This is very rare in solid electrolytes, clearing a major obstacle for the commercialization of all solid state batteries.
"But it should be noted that this new material is not perfect." Ma Cheng said frankly that the stability of lithium zirconium chloride for lithium metal anode is not good, which still needs to be addressed. At present, the team is trying to improve the stability of lithium zirconium chloride on metal lithium, and research and develop high energy density flexible battery based on lithium zirconium chloride, continuously optimize the performance of all solid state lithium battery, and cooperate with relevant enterprises to promote the commercialization process.