All-Solid-State Battery Commercialization Accelerated... Core Electrolyte Achieves Both Performance and Safety

Korea Institute of Industrial Technology Develops Sulfide-Based Solid Electrolyte
Ionic Conductivity Increased 77-Fold, Toxic Gas Emissions Reduced by 40%

A domestic research team has proposed a solution to the biggest challenge in the commercialization of all-solid-state batteries: achieving both rapid ion mobility and air stability.

The Korea Institute of Industrial Technology has developed a core material that enhances both the performance and safety of sulfide-based solid electrolytes, reducing the risk of fire while simultaneously increasing charging speed and battery lifespan. This breakthrough is expected to accelerate the commercialization timeline of next-generation batteries.

All-solid-state pressurized cell applying developed electrolyte. Provided by Saenggiyun

The Korea Institute of Industrial Technology announced on April 15 that the research team led by Senior Researcher Kim Taehyo of the Low Carbon Energy Group succeeded in improving both performance and moisture stability of the sulfide-based solid electrolyte lithium hexathiophosphate iodide (Li6PS5I) by introducing three elements: chlorine (Cl), antimony (Sb), and oxygen (O).

Sulfide-based solid electrolytes are key materials in all-solid-state batteries, serving as the pathway through which lithium ions travel between the cathode and anode. Although their high ionic conductivity makes them strong candidates, their susceptibility to moisture has been a limitation, as exposure to humidity leads to the production of toxic hydrogen sulfide (H₂S).

The research team addressed this issue by assigning distinct roles to the three elements. Chlorine disrupted the internal atomic arrangement of the material, broadening the channels for lithium-ion migration. Antimony and oxygen formed stronger chemical bonds, which reduced both the decomposition of the material and hydrogen sulfide generation upon exposure to moisture.

Simultaneous Improvement in Charging Speed and Safety...Stable Operation for 100 Cycles in Demonstration Cell

As a result, the ionic conductivity of the developed material reached 1.158 mS/cm, which is approximately 77 times higher than conventional materials. The amount of hydrogen sulfide generated at 30% relative humidity was reduced by 40%, and even after 24 hours at 50% humidity, the new material remained solid, while existing materials collapsed into a muddy state.

Research team holding an all-solid-state battery cell applying the developed electrolyte. Jinyoung Bae, self-intern (first author, left), and Taehyo Kim, senior researcher (corresponding author). Provided by Korea Institute of Energy Research

Interfacial stability with lithium metal also improved. The critical current value withstood up to just before internal short-circuit in the battery increased by 86% compared to previous materials, and a symmetric cell in contact with lithium metal operated stably for over 1,000 hours.

Notably, the research team went beyond material-level experiments by assembling an actual pressurized cell to verify battery performance. The all-solid-state battery using the developed electrolyte achieved an initial discharge capacity of 158.4 mAh/g, an improvement of about 18% over previous versions, and maintained stable operation even after 100 charge-discharge cycles.

Senior Researcher Kim stated, "We have demonstrated the potential for material design that can enhance both performance and stability in sulfide-based solid electrolytes. We plan to transfer this technology to domestic materials, parts, and equipment companies to accelerate the commercialization of all-solid-state batteries."

This achievement has been published in the international journal Chemical Engineering Journal.

This content was produced with the assistance of AI translation services.