South Korean battery maker SK On has discovered a method to enhance the cycle life of sulfide-based all-solid-state lithium batteries.
SK On’s research, conducted in collaboration with Dr. Dong-Won Kim’s group at Hanyang University in Seoul, introduces a method for forming a protective layer on the lithium metal anode surface to enhance battery safety and extend its lifespan. The team has filed patent applications for its key findings.
Lithium metal anodes typically demonstrate limited charge-discharge cycles. To address this, the research team removed the resistive surface layer by immersing the anode in a specially formulated solution. This resulted in the formation of a protective layer featuring high ionic conductivity, attributed to lithium nitrate, and enhanced mechanical strength owing to lithium oxide.
SK On said this method ensured interfacial stability. Experimental results show that the surface-modified anode enables stable cycling for over 300 charge-discharge cycles at room temperature, tripling the cycle life compared to conventional lithium metal all-solid-state batteries.
The study was published last month in energy and chemistry journal ACS Energy Letters.
Also, in collaboration with Dr. Jong Hyeok Park of Yonsei University, SK On has uncovered the relationship between battery life and the thermal curing time of gel polymer electrolytes (GPEs). Their study was published in the journal Angewandte Chemie in February.
According to the study, longer thermal curing times for the GPEs resulted in better retention of battery performance. The study showed that batteries using electrolytes that had 60 minutes of thermal curing showed a 9.1% decrease in discharge capacity, while those that had just 20 minutes of thermal curing experienced a 34% decrease.
This suggests that shorter thermal curing time leads to the easy decomposition of the cathode protective layer, which in turn reduces capacity and ultimately shortens battery lifespan. The team also applied density functional theory calculations to identify the cause and mechanism of cathode performance degradation and investigate residual monomer-induced side reactions during the initial charging stage. SK On said the findings from this study are expected to contribute to improving the lifespan of polymer-oxide composite-based batteries.
“These achievements are the result of SK On’s continued R&D efforts and technological prowess, enabled through collaboration with academia,” said Kisoo Park, Head of R&D at SK On. “They will serve as a key foundation for overcoming the technological challenges of solid-state batteries.”
SK On is developing two types of all-solid-state batteries: polymer-oxide composite and sulfide-based. The company is targeting commercialization in 2028 and 2030, respectively.
Source: SK On
