A group at the National High Magnetic Field Laboratory, based at Florida State University, has uncovered the process by which tiny metallic lithium needles, called dendrites, form during the operation of solid-state batteries, leading to short circuits and battery malfunction.
The study conducted by the team, published in Nature Materials, enhances the understanding of dendrite development and may contribute to the creation of safer and more efficient solid-state batteries for diverse applications such as electric vehicles, energy systems, medical devices, and beyond.
“Understanding the issue is crucial for addressing it,” stated Yan-Yan Hu, a professor of chemistry and biochemistry at FSU who led the investigation. “We aim to decipher the processes involved in dendrite creation within solid materials.”
The investigation allows a detailed observation of the internal dynamics of a solid-state lithium battery as it undergoes cycles of discharge and recharge. The researchers achieved unprecedented imagery by crafting a specialized probe that enables them to visualize the inside of the battery during these cycles, utilizing the MagLab’s world-leading magnetic resonance imaging apparatus.
HOW IT FUNCTIONS:
Solid-state batteries, which utilize a solid electrolyte instead of a liquid or gel, represent a cutting-edge technology poised to transform energy storage for electric automobiles, consumer gadgets, and renewable energy devices. They offer superior energy density while eliminating safety concerns associated with traditional liquid lithium-ion batteries, which are prone to overheating or igniting.
Nonetheless, the quest to produce dependable solid-state lithium batteries encounters a unique challenge: the formation of dendrites. As the battery operates, these minute metallic lithium needles emerge and spread throughout the material akin to growing trees, intertwining with each other and causing short circuits in the battery.
Now, after over five years of exploration utilizing unique magnets and specialized methods, a team at the MagLab has gained clearer insight into the precise locations and mechanisms of dendrite creation.
The research team monitored the charging and discharging of batteries within the nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) probe and scrutinized dendrite emergence inside the batteries to better understand the formation process.
“Our high-field magnets at the MagLab are exceptional for analyzing often challenging-to-detect elements such as lithium, expanding the periodic table to visualize elements that are not accessible at lower magnetic fields,” remarked Sam Grant, a professor of chemical and biomedical engineering at FSU and the director of the MagLab’s MRI initiative, who serves as a senior author on this research.
The team also devised a distinctive method to chemically trace the source of dendrite formation—identifying whether it originated from lithium at the edge or center of the battery. The battery was cycled multiple times while researchers kept a close watch on the development of dendrites.
“A standout feature of this study is the integration of high-field MRI with NMR.
MRI captures the distribution and progression of dendrite formation, while NMR sheds light on the chemistry and origins of the lithium accumulating as dendrites,” Grant explained.
The experimental battery was composed of two solid lithium electrodes flanking a solid electrolyte compound known as LLZO: lithium lanthanum and zirconium oxide.
Their research clarified the intricate interactions between two processes that lead to dendrite generation. The lithium needles initially accumulate at the juncture of the battery’s electrode and electrolyte. The electrode serves as the connection for the battery terminal to the electrolyte, facilitating the transport of charged particles throughout the battery. The researchers also discovered that additional dendrites emerge in the center of the solid electrolyte as the battery is cycled. These dendrites at both the edges and centers then grow and may connect, resulting in short circuits and battery defects.
“We now possess a thorough understanding of how these dendrites can arise, develop, and change,” noted Yudan Chen, a Florida State University graduate student and one of the paper’s lead authors.
WHY IT IS SIGNIFICANT:
Solid-state batteries find utility across a variety of fields, encompassing electric vehicles, medical instruments, wearable technology, and more. This innovation has the potential to enhance battery performance in numerous sectors by providing a more secure, efficient, and durable power source compared to current technologies. However, there remain challenges related to production, costs, and scaling that need to be tackled before they can supplant traditional batteries on a large scale.
With the newfound knowledge of the causes of dendrite accumulation and battery degradation, this research paves the way for the development of superior solid-state batteries.
Scientists are also keen to explore how this research can facilitate advancements in alternative and sustainable energy derived from natural resources.
“We have numerous methods to generate energy,” said Chen. “The primary challenge is figuring out how we can store that generated energy for later use when it’s required.”
FUTURE PATHS:
The next phase involves investigating strategies to inhibit dendrite growth and enhance battery configurations.
The challenge will involve adjusting the battery’s materials and design to reduce dendrites. This may encompass employing a different blend of components, redesigning the interface where the electrode interfaces with the electrolyte, and modifying the microstructure of the solid electrolyte.
“We have concepts and potential strategies to engineer and redesign our battery cell,” expressed Chen, “and afterwards, we can apply our magnetic resonance methodologies here to assess whether our engineering techniques can be effective in truly alleviating dendrite formation. We can utilize this as a tool for evaluation.”
The article National High Magnetic Field Laboratory researchers decipher cause of solid-state battery breakdowns first appeared on Florida State University News.