Domestic researchers have developed a technology to solve the performance degradation problem of all-solid-state batteries. They stacked solid electrolytes in three layers to endow the necessary characteristics for performance enhancement.
The research team led by Kim Jae-hyun, head researcher at the Daegu Gyeongbuk Institute of Science and Technology (DGIST) Energy and Environment Research Division, announced on the 26th that they have developed a "triple-layer polymer solid electrolyte" battery that reduces fire risk while maintaining excellent performance.
Lithium batteries consist of liquid electrolytes and anodes and cathodes, providing high energy density and capacity, making them widely used in smartphones, electric vehicles, and across the industry. However, there are drawbacks, as the organic materials in the liquid electrolytes are easily ignited, and the separator that separates the anode and cathode can be damaged, leading to short circuits and fire vulnerability. While research is ongoing into all-solid-state battery technology using solid electrolytes with reduced fire risks, commercialization is still not achieved due to performance and expense issues.
To address these issues, the research team developed an all-solid-state battery with a "triple-layer structure" made up of three electrolyte layers. Existing all-solid-state batteries have faced challenges in achieving complete contact between electrodes and electrolytes, making substantial performance improvements difficult. Additionally, lithium ions can form sharp metallic "dendrites" during repetitive charging and discharging, leading to rapid performance degradation.
The triple-layer structure developed by the research team increases battery safety and performance by having each of the three layers serve distinct roles. It uses "DBDPE" to prevent the electrolyte from igniting easily, "zeolite" to enhance the electrolyte's strength, and high-concentration lithium salt "LiTFSI" to aid in the movement of lithium ions, thus reducing fire risk and improving performance. The surface of the electrolyte is smooth, allowing good contact with the electrodes to facilitate lithium ion movement and minimize dendrite formation. The interior of the electrolyte is solid, providing excellent mechanical strength.
Performance tests show that the battery developed by the research team retains 87.9% of its initial performance after 1,000 charge and discharge cycles. In contrast, existing all-solid-state batteries drop to 70-80% under the same conditions. Even when ignited, the battery extinguishes itself, significantly reducing fire hazards.
Kim noted, "We expect that the commercialization of polymer solid electrolyte-based lithium metal batteries can be expedited," adding that it could also enhance the stability and efficiency of energy storage systems.
The research findings were introduced in the international journal "Small" on the 3rd of last month.
Reference material
Small (2024), DOI: https://doi.org/10.1002/smll.202406200