Our lives today are governed by electronics in all shapes and forms. Electronics, in turn, are governed by their batteries. However, the traditional lithium-ion batteries (LIBs), that are widely used in electronic devices, are falling out of favor because researchers are beginning to view lithium metal batteries (LMBs) as a superior alternative due to their remarkably high energy density that exceeds LIBs by an order of magnitude! The key difference lies in the choice of anode material: LIBs use graphite, whereas LMBs use lithium metal.
Such a choice, however, comes with its own challenges. Among the most prominent ones is the formation of needle-like structures on the lithium anode surface during cycling called "dendrites" that tend to pierce the barrier between the anode and cathode, causing short-circuit and, consequently, safety issues. "Li dendrite formation is strongly dependent on the surface nature of lithium anodes. A crucial strategy for LMBs, therefore, is to build an efficient solid-electrolyte interface (SEI) at the lithium surface," explains Prof. Yong Min Lee from Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea, who specializes in battery design.
Accordingly, researchers have explored a variety of strategies, from 2D interfacial engineering to 3D lithium anode architecture. In each case, solving one problem has merely given way to another. However, a new approach based on lithium metal powder (LMP) composite electrodes promises to stand out. The appeal of LMP lies in their spherical shape, which results in higher surface area, and ease of thickness tunability, allowing for wider and thinner electrodes. However, problems with LMP use still exist, such as the morphological failure caused by the inherent nature of their uneven surface.
Now, in a new study published in Advanced Energy Materials, Dr. Lee, along with researchers from Korea, adopted a novel approach in which they pre-planted LiNO3 to the LMP itself during the electrode fabrication process, allowing them to fabricate ~150-mm-wide and 20-μm-thick electrodes, which showed a coulombic efficiency of 96%.
The addition of LiNO3 to LMP accomplished two things: it induced a uniform N-rich SEI on the LMP surface and led to its sustained stabilization over prolonged cycling as LiNO3 was steadily released into the electrolyte. In fact, LMBs with LiNO3 pre-planted LMP (LN-LMP) demonstrated an outstanding cycling performance, with 87% capacity retention over 450 cycles, outperforming even cells with LiNO3-added electrolytes.
Prof. Lee is thrilled by these findings and speaks of their practical ramifications. "We expect that pre-planting Li stabilized additives into the LMP electrode would be a stepping-stone towards the commercialization of large-scale Li-metal, Li-S, and Li-air batteries with high specific energy and long cycle life," he says.
With respect to batteries, it looks like lithium is not going out of fashion anytime soon!
Authors: Dahee Jin1, Youngjoon Roh1, Taejin Jo2, Myung-Hyun Ryou3, Hongkyung Lee1,4 and Yong Min Lee1,4
Title of original paper: Robust Cycling of Ultrathin Li Metal Enabled by Nitrate-Preplanted Li Powder Composite
Journal: Advanced Energy Materials
Affiliations: 1Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST)
3Department of Chemical and Biological Engineering, Hanbat National University
4Energy Science and Engineering Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST)
About Daegu Gyeongbuk Institute of Science and Technology (DGIST)
Daegu Gyeongbuk Institute of Science and Technology (DGIST) is a well-known and respected research institute located in Daegu, Republic of Korea. Established in 2004 by the Korean Government, the main aim of DGIST is to promote national science and technology, as well as to boost the local economy. With a vision of "Changing the world through convergence", DGIST has undertaken a wide range of research in various fields of science and technology. DGIST has embraced a multidisciplinary approach to research and undertaken intensive studies in some of today's most vital fields. DGIST also has state-of-the-art-infrastructure to enable cutting-edge research in materials science, robotics, cognitive sciences, and communication engineering.
About the author
Dr. Yong Min Lee is currently an Associate Professor at the Department of Energy Science and Engineering in DGIST, Republic of Korea, since 2017. He earned his Ph.D. at Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea, in 2007. His research interests are functional materials for batteries, battery design/advanced analysis, and 3D modeling/simulations. He has published 167 papers with over 6800 citations to his credit and is a recipient of several awards, including the latest research award in 2020 and the best lecture award in 2019.
Advanced Energy Materials