Single-crystal Cu foil offers new pathways to mitigate fire and explosion risks in lithium batteries – Tech Xplore
Lithium-ion batteries are the powerhouses of our portable electronic devices and electric vehicles, but their use comes with inherent risks: they can catch fire or even explode if mishandled. These hazards stem from the formation of dendrites—needle-like structures that can grow on the lithium metal anode during charging, eventually shorting out the battery and triggering catastrophic failures.
Now, researchers at the Institute for Basic Science (IBS), Korea have introduced a groundbreaking solution that could potentially pave the way for safer and more reliable batteries. In a new study published in *Nature Materials*, they unveiled the potential of single-crystal Cu foil to address the dendrite problem, thus safeguarding the battery against unwanted thermal runaway.
The IBS team led by Professor Hyeon-Jin Shin, from the Center for Nanoparticle Research, had previously demonstrated that single-crystal metal structures could excel in electrocatalysis by providing fast electron pathways. Now, they ventured into the world of batteries and revealed that single-crystal Cu foils, unlike conventional polycrystalline counterparts, effectively suppress dendrite growth. These nanocrystals possess exceptional structural integrity and smooth surfaces, creating a hostile environment for lithium dendrite formation.
“Dendrite formation during battery charging is a significant obstacle for its practical application, particularly for large-scale energy storage,” says Prof. Shin, “We found that single-crystal Cu foil prevents the growth of lithium dendrites, thanks to its unique structure and excellent properties.”
To understand the remarkable impact of single-crystal Cu foils, the IBS team first performed detailed analysis using a transmission electron microscope. They observed that dendrites grow significantly more slowly on a single-crystal Cu foil compared to a conventional polycrystalline foil. Furthermore, the researchers identified a crucial factor behind this exceptional performance—the lower interfacial energy between single-crystal Cu and lithium.
“Interfacial energy between different materials, including lithium and Cu, is directly related to the tendency of lithium ions to gather,” says Dr. Taejun Park, the first author of this study, “When the interfacial energy is low, lithium ions spread across the entire surface, reducing the density at specific locations and thus mitigating the formation of lithium dendrites.”
But the researchers’ findings didn’t stop there. Their investigations also revealed the significance of grain boundaries, which are the interfaces between individual crystalline grains in polycrystalline materials. These grain boundaries act as potential nucleation sites for dendrite formation due to their uneven energy distribution. In single-crystal Cu foil, devoid of grain boundaries, dendrite growth is effectively suppressed.
“The absence of grain boundaries significantly contributes to the excellent properties of single-crystal Cu foil,” explains Dr. Junghoon Jang, a senior researcher in the team. “It essentially inhibits lithium dendrite formation, thereby enhancing battery performance and safety.”
These advancements represent a significant breakthrough in the field of lithium-ion batteries. By demonstrating the effectiveness of single-crystal Cu foil in combating dendrite formation, the IBS team has laid the groundwork for more reliable and safe battery technologies. This research offers promising pathways towards widespread adoption of lithium batteries in various applications, contributing to the development of sustainable energy solutions.
While single-crystal Cu foils have already shown promise in experimental setups, there is still much work to be done before they can be implemented in commercial batteries. The next challenge lies in the development of scalable fabrication methods for producing large single-crystal Cu foils at low costs. Additionally, understanding the long-term stability of these materials in real-world battery settings is essential to ensure their reliable performance.
Despite these challenges, this groundbreaking study from IBS paves the way for a future with safer and more efficient lithium batteries. It’s a testament to the potential of cutting-edge materials science to address real-world problems and unlock the full potential of energy storage solutions.
