Faster and higher-quality production of lithium superionic conductors for all-solid-state batteries

Dr. Ha Yoon-Cheol’s workforce at KERI’s Subsequent Technology Battery Analysis Heart has developed an “enhanced coprecipitation method” that allows quicker and higher-quality manufacturing of lithium superionic conductors for all-solid-state batteries (ASSBs). ASSB replaces the “electrolyte,” which transfers ions between the anode and cathode, with a stable as a substitute of a liquid, considerably decreasing the chance of fireside or explosion.

Strong electrolytes are troublesome to fabricate and costly. Nonetheless, in 2021, Dr. Ha Yoon-Cheol’s workforce garnered vital consideration by proposing the “coprecipitation method,” which permits large-scale manufacturing of solid electrolytes by means of a one-pot resolution course of, with out the necessity for costly lithium sulfide (Li₂S) by instantly including the uncooked supplies right into a single container.

This methodology considerably reduces uncooked materials prices in comparison with typical strategies and doesn’t require high-energy milling or evaporation processes. The know-how has been transferred to Daejoo Digital Supplies Co., Ltd., a home firm specializing in electrical and digital supplies.

Since then, KERI has continued follow-up analysis with KAIST, Daejoo Digital Supplies Co., Ltd., and others. By these efforts, they efficiently recognized the detailed mechanisms behind the dissolution and coprecipitation phenomena, resulting in the event of an optimized, upgraded coprecipitation methodology that considerably shortens manufacturing time and dramatically improves the standard of stable electrolytes.

The important thing to the coprecipitation methodology is the method of evenly dissolving the uncooked supplies in an answer, precipitating them, after which filtering them out. Dr. Ha Yoon-Cheol’s workforce first blended lithium, sulfur, and catalyst within the optimum proportions, and analyzed the method through which lithium polysulfides and lithium sulfide are sequentially shaped relying on the diploma of lithium dissolution.

They then utilized this to the synthesis processes of three-element (resembling Li₃PS₄) and four-element (resembling Li₆PS₅Cl) stable electrolytes, creating a know-how that allows speedy and homogeneous dissolution and coprecipitation of assorted uncooked supplies.

The detailed mechanism evaluation of KERI’s coprecipitation methodology was carried out by prime researchers from main universities in Korea. Professor Byon Hye Ryung’s workforce at KAIST led the chemical evaluation of the intermediate species shaped relying on the diploma of lithium dissolution.

Moreover, quantum calculations and anion mass spectrometry carried out by Professor Baek Moo-Hyeon’s workforce at KAIST and Professor Search engine marketing Jongcheol’s workforce at POSTECH performed a vital position in uncovering the correct molecular constructions. Primarily based on this, Daejoo Digital Supplies Co., Ltd. integrated the know-how associated to steady processes that shall be utilized within the precise mass manufacturing of stable electrolytes.

By steady collaboration between business, academia, and analysis institutes, the upgraded coprecipitation methodology was developed, considerably decreasing the manufacturing time of stable electrolytes from 14 hours to simply 4 hours.

The standard of the optimally synthesized stable electrolytes has additionally been improved. Typical manufacturing strategies confronted a persistent problem of decrease ionic conductivity in the course of the scale-up course of. Nonetheless, with the appliance of the upgraded coprecipitation methodology within the scale-up course of, the ion conductivity of the stable electrolytes reached 5.7 mS/cm. This surpasses the extent of liquid electrolytes (~4 mS/cm).

As well as, by making use of the stable electrolytes to a 700mAh ASSB pouch cell, which is about one-fifth the capability of a smartphone battery, an vitality density of 352Wh/kg was achieved, surpassing the energy density of economic lithium-ion batteries (270Wh/kg). Furthermore, in experiments the place the ASSB was charged and discharged 1,000 instances, it maintained over 80% of its capability, confirming its secure lifespan.

The analysis outcomes have been published within the journal Vitality Storage Supplies. The analysis workforce has confirmed that this know-how will be utilized not solely to the synthesis of stable electrolytes but additionally to the manufacturing of assorted practical coatings. Just lately, a patent for the know-how has additionally been filed.

Dr. Ha Yoon-Cheol of KERI acknowledged, “The previous achievement was significant in that it introduced the coprecipitation technology for the first time in the world to the manufacturing process of solid electrolytes, while this upgraded method is a result of optimizing the principles of the coprecipitation method through detailed analysis, leading to better outcomes.”

“This will serve as a key enabler for opening an era of mass production of ASSBs at a low cost.”