New discovery could lead to smaller, lighter, cheaper car batteries -Lithium - Ion Battery Equipment
According to foreign media reports, a team of researchers at the Brookhaven National Laboratory (Brookhaven National Laboratory) of the US Department of Energy (DOE) has determined new details about the internal reaction mechanism of lithium metal anode batteries. A major step forward for smaller, lighter and cheaper electric vehicle batteries.
Brookhaven National Laboratory battery researchers (: Brookhaven National Laboratory)
Reinventing Lithium Metal Anodes
Traditional lithium-ion batteries, found in everything from smartphones to electric vehicles, have enabled many technologies to be widely used, but they still face challenges in powering electric vehicles over long distances.
In order to create a battery more suitable for electric vehicles, a number of US national laboratories led by DOE Pacific Northwest National Laboratory (PNNL) and university researchers funded by DOE have established a consortium called Battery500, with the goal of creating energy density The battery cell is 500Wh/kg, that is, the energy density is twice that of today's most advanced batteries. To that end, the consortium is focusing on batteries made with lithium metal anodes.
Compared with lithium-ion batteries, which mostly use graphite as the anode, lithium metal batteries use lithium metal as the anode. The researchers said: "The lithium metal anode is one of the key factors to meet the energy density target of Battery500. The advantage is that its energy density is twice that of existing batteries. First, the specific capacity of this anode is high; second, it can achieve A battery with a higher voltage, the combination of the two can achieve a higher energy density."(Lithium - Ion Battery Equipment)
Scientists have long recognized the advantages of lithium metal anodes; in fact, lithium metal anodes were the first to be coupled to the cathode of a battery. But because the anode lacks "reversibility," the ability to charge through a reversible electrochemical reaction, battery researchers eventually replaced the lithium metal anode with a graphite anode to create a lithium-ion battery.
Now, after decades of progress, researchers are confident of achieving reversible lithium metal anodes to push beyond the limits of lithium-ion batteries. The key lies in the interface, the layer of solid material that forms on the battery's electrodes during the electrochemical reaction.
"If we can fully understand this interface, it can provide important guidance for materials design and build reversible lithium metal anodes," the researchers said. However, understanding this interface is a considerable challenge because it is a very Thin material layers, only a few nanometers thick, are also sensitive to air and humidity, so handling such samples is tricky."
Visualize this interface in NSLS-II
To address the aforementioned challenge of "seeing" the chemical makeup and structure of this interface, the researchers employed the National Synchrotron Light Source II (NSLS-II), a user device at Brookhaven National Laboratory's DOE Office of Science, to generate ultrabright The X-rays are used to study the material properties of this interface from the atomic scale.
In addition to exploiting the advanced capabilities of NSLS-II, the research team needed to probe the crystalline phase as well as the amorphous phase with high-energy (short-wavelength) X-rays using a beamline (experiment station) capable of probing all components of the interface. This beamline is the beamline of X-ray powder diffraction (XPD).
"The chemistry team took the multimodal approach of XPD, taking advantage of two different techniques offered by the beamline, X-ray diffraction (XRD) and pair distribution function (PDF) analysis. XRD enables the study of crystalline phases, while PDF able to study amorphous phases."
XRD and PDF analyzes reveal a pleasing result: the presence of lithium hydride (LiH) within the interface. For decades, scientists have debated whether LiH exists within the interface, thus creating uncertainty about the fundamental reaction mechanism for the formation of the interface.
"LiH and lithium fluoride (LiF) have very similar crystal structures, and our claim to have discovered LiH has been challenged by some who believe that we have mistaken LiF for LiH," the researchers said.
Considering the controversy involved in this study, and the technical challenges in distinguishing LiH from LiF, the research team decided to provide multiple lines of evidence for the existence of LiH, including air exposure experiments.
Brookhaven National Laboratory battery researchers (: Brookhaven National Laboratory)
Reinventing Lithium Metal Anodes
Traditional lithium-ion batteries, found in everything from smartphones to electric vehicles, have enabled many technologies to be widely used, but they still face challenges in powering electric vehicles over long distances.
In order to create a battery more suitable for electric vehicles, a number of US national laboratories led by DOE Pacific Northwest National Laboratory (PNNL) and university researchers funded by DOE have established a consortium called Battery500, with the goal of creating energy density The battery cell is 500Wh/kg, that is, the energy density is twice that of today's most advanced batteries. To that end, the consortium is focusing on batteries made with lithium metal anodes.
Compared with lithium-ion batteries, which mostly use graphite as the anode, lithium metal batteries use lithium metal as the anode. The researchers said: "The lithium metal anode is one of the key factors to meet the energy density target of Battery500. The advantage is that its energy density is twice that of existing batteries. First, the specific capacity of this anode is high; second, it can achieve A battery with a higher voltage, the combination of the two can achieve a higher energy density."(Lithium - Ion Battery Equipment)
Scientists have long recognized the advantages of lithium metal anodes; in fact, lithium metal anodes were the first to be coupled to the cathode of a battery. But because the anode lacks "reversibility," the ability to charge through a reversible electrochemical reaction, battery researchers eventually replaced the lithium metal anode with a graphite anode to create a lithium-ion battery.
Now, after decades of progress, researchers are confident of achieving reversible lithium metal anodes to push beyond the limits of lithium-ion batteries. The key lies in the interface, the layer of solid material that forms on the battery's electrodes during the electrochemical reaction.
"If we can fully understand this interface, it can provide important guidance for materials design and build reversible lithium metal anodes," the researchers said. However, understanding this interface is a considerable challenge because it is a very Thin material layers, only a few nanometers thick, are also sensitive to air and humidity, so handling such samples is tricky."
Visualize this interface in NSLS-II
To address the aforementioned challenge of "seeing" the chemical makeup and structure of this interface, the researchers employed the National Synchrotron Light Source II (NSLS-II), a user device at Brookhaven National Laboratory's DOE Office of Science, to generate ultrabright The X-rays are used to study the material properties of this interface from the atomic scale.
In addition to exploiting the advanced capabilities of NSLS-II, the research team needed to probe the crystalline phase as well as the amorphous phase with high-energy (short-wavelength) X-rays using a beamline (experiment station) capable of probing all components of the interface. This beamline is the beamline of X-ray powder diffraction (XPD).
"The chemistry team took the multimodal approach of XPD, taking advantage of two different techniques offered by the beamline, X-ray diffraction (XRD) and pair distribution function (PDF) analysis. XRD enables the study of crystalline phases, while PDF able to study amorphous phases."
XRD and PDF analyzes reveal a pleasing result: the presence of lithium hydride (LiH) within the interface. For decades, scientists have debated whether LiH exists within the interface, thus creating uncertainty about the fundamental reaction mechanism for the formation of the interface.
"LiH and lithium fluoride (LiF) have very similar crystal structures, and our claim to have discovered LiH has been challenged by some who believe that we have mistaken LiF for LiH," the researchers said.
Considering the controversy involved in this study, and the technical challenges in distinguishing LiH from LiF, the research team decided to provide multiple lines of evidence for the existence of LiH, including air exposure experiments.
