An international team of scientists has identified a surprising factor that accelerates the degradation of lithium-ion batteries leading to a steady loss of charge. This discovery provides a new understanding of battery life and offers strategies to combae
Kaunas University of Technology
Artūras Vailionis, a core lead of the X-ray and Surface Analysis group at Stanford University and a visiting professor at the Lithuanian Kaunas University of Technology (KTU)
Credit: Artūras Vailionis
An international team of scientists has identified a surprising factor that accelerates the degradation of lithium-ion batteries leading to a steady loss of charge. This discovery provides a new understanding of battery life and offers strategies to combat self-discharge, which could improve performance in various applications from smartphones to electric vehicles.
According to Artūras Vailionis, a core lead of the X-ray and Surface Analysis group at Stanford University and a visiting professor at the Lithuanian Kaunas University of Technology (KTU), it has been (and still is) commonly believed that the self-discharge of a fully charged battery is due to the diffusion of lithium atoms from the electrolyte to the battery’s cathode.
“However, our study has shown that it is the diffusion of protons (hydrogen ions) that is causing a battery’s self-discharge. Based on the results of this study, it is possible to propose ways to extend the life of the battery by reducing self-discharge,” says Vailionis.
These ways may include supplementing additives to the electrolyte that do not contain hydrogen molecules, such as CH2, or using a special coating to reduce the cathode surface’s reaction with the electrolyte.
Longer battery life for greener and more cost-effective technologies
Prof. Vailionis explains that self-discharge shortens both the calendar and cyclic life of the battery, and over time it causes a decrease in its voltage and capacity. The limited lifespan of a lithium battery has environmental and economic impacts; therefore, it is important to understand and prevent this issue.
The discovery of an entirely new phenomenon behind the self-discharge of the batteries might pave the way to greener, more cost-effective and more reliable technology.
“The longer lifetime of lithium-ion batteries means that consumers need to change their batteries or electronic devices less often. Also, longer battery life helps to reduce the amount of electronic waste and prevents resource depletion – lithium, cobalt, and nickel are finite resources – thus contributing to more sustainable practices,” says Vailionis, a visiting professor at KTU, Lithuania.
Devices with long-lasting batteries, such as smartphones, laptops and others, can be used for longer without the need to recharge them, and in industrial applications with large battery systems (e.g. electric vehicles or grid energy storage), longer battery life means a higher return on investment, making these technologies more economical. Besides, in renewable energy systems, such as solar and wind power, longer battery life increases the efficiency and reliability of energy storage, helps stabilise the energy supply and reduces dependence on fossil fuels.
As lithium-ion batteries are also used in medical devices, aerospace and defence systems, longer battery life reduces the risk of failure in critical situations.
“Overall, longer battery life improves sustainability, economy and productivity in a wide range of industrial applications,” adds Vailionis.
The outcome of the large international group of scientists
Prof. Vailionis emphasises that the study results are the outcome of the work of a large international group of scientists from different fields. Vailionis’s team at Stanford University used X-ray diffraction to identify two different structures in the cathode: one at the surface (the one affected by hydrogen ions) and one deeper inside the cathode. X-ray reflectometry also confirmed the existence of a surface layer with hydrogen atoms.
Vailionis, a Stanford University scientist, has been a visiting professor at KTU, Lithuania for 13 years. Every year, he gives a course on X-ray diffraction to the students of the physics study programmes and takes part in common projects with KTU scientists.
“Since I left, Lithuania has changed beyond recognition: universities are getting much better funding for education, they have access to European funds. Scientists and PhD students have great opportunities to go to other universities and research institutions to study, to go to conferences and to share their research results,” says a KTU visiting professor.
According to him, Lithuanian students have also changed: “They are much more active in the class than they were in my time, and there are no problems with the English language.”
Journal
Science
DOI
10.1126/science.adg4687
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Solvent-mediated oxide hydrogenation in layered cathodes
Developing advanced recycling technology to restore spent battery cathode materials
The recycling process restores spent batteries to 100% of their original capacity, making them equivalent to new batteries
An international team of scientists has identified a surprising factor that accelerates the degradation of lithium-ion batteries leading to a steady loss of charge. This discovery provides a new understanding of battery life and offers strategies to combat self-discharge, which could improve performance in various applications from smartphones to electric vehicles.
According to Artūras Vailionis, a core lead of the X-ray and Surface Analysis group at Stanford University and a visiting professor at the Lithuanian Kaunas University of Technology (KTU), it has been (and still is) commonly believed that the self-discharge of a fully charged battery is due to the diffusion of lithium atoms from the electrolyte to the battery’s cathode.
“However, our study has shown that it is the diffusion of protons (hydrogen ions) that is causing a battery’s self-discharge. Based on the results of this study, it is possible to propose ways to extend the life of the battery by reducing self-discharge,” says Vailionis.
These ways may include supplementing additives to the electrolyte that do not contain hydrogen molecules, such as CH2, or using a special coating to reduce the cathode surface’s reaction with the electrolyte.
Longer battery life for greener and more cost-effective technologies
Prof. Vailionis explains that self-discharge shortens both the calendar and cyclic life of the battery, and over time it causes a decrease in its voltage and capacity. The limited lifespan of a lithium battery has environmental and economic impacts; therefore, it is important to understand and prevent this issue.
The discovery of an entirely new phenomenon behind the self-discharge of the batteries might pave the way to greener, more cost-effective and more reliable technology.
“The longer lifetime of lithium-ion batteries means that consumers need to change their batteries or electronic devices less often. Also, longer battery life helps to reduce the amount of electronic waste and prevents resource depletion – lithium, cobalt, and nickel are finite resources – thus contributing to more sustainable practices,” says Vailionis, a visiting professor at KTU, Lithuania.
Devices with long-lasting batteries, such as smartphones, laptops and others, can be used for longer without the need to recharge them, and in industrial applications with large battery systems (e.g. electric vehicles or grid energy storage), longer battery life means a higher return on investment, making these technologies more economical. Besides, in renewable energy systems, such as solar and wind power, longer battery life increases the efficiency and reliability of energy storage, helps stabilise the energy supply and reduces dependence on fossil fuels.
As lithium-ion batteries are also used in medical devices, aerospace and defence systems, longer battery life reduces the risk of failure in critical situations.
“Overall, longer battery life improves sustainability, economy and productivity in a wide range of industrial applications,” adds Vailionis.
The outcome of the large international group of scientists
Prof. Vailionis emphasises that the study results are the outcome of the work of a large international group of scientists from different fields. Vailionis’s team at Stanford University used X-ray diffraction to identify two different structures in the cathode: one at the surface (the one affected by hydrogen ions) and one deeper inside the cathode. X-ray reflectometry also confirmed the existence of a surface layer with hydrogen atoms.
Vailionis, a Stanford University scientist, has been a visiting professor at KTU, Lithuania for 13 years. Every year, he gives a course on X-ray diffraction to the students of the physics study programmes and takes part in common projects with KTU scientists.
“Since I left, Lithuania has changed beyond recognition: universities are getting much better funding for education, they have access to European funds. Scientists and PhD students have great opportunities to go to other universities and research institutions to study, to go to conferences and to share their research results,” says a KTU visiting professor.
According to him, Lithuanian students have also changed: “They are much more active in the class than they were in my time, and there are no problems with the English language.”
Journal
Science
DOI
10.1126/science.adg4687
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Solvent-mediated oxide hydrogenation in layered cathodes
Developing advanced recycling technology to restore spent battery cathode materials
The recycling process restores spent batteries to 100% of their original capacity, making them equivalent to new batteries
National Research Council of Science & Technology
image:
Spent cathode material immersed in restorative solution.
Credit: KOREA INSTITUTE OF ENERGY RESEARCH
A research team led by Dr. Jung-Je Woo at the Gwangju Clean Energy Research Center of the Korea Institute of Energy Research (KIER) has successfully developed a cost-effective and eco-friendly technology for recycling cathode materials* from spent lithium-ion batteries.
*Cathode Materials: Materials that play a crucial role in generating electricity by storing and releasing lithium ions during battery charging and discharging.
With the recent rise in electric vehicles and mobile devices, managing spent batteries has become a critical global challenge. By 2040, the number of decommissioned electric vehicles is expected to exceed 40 million*, leading to a sharp increase in waste batteries. Developing advanced recycling technologies has thus become an urgent priority, as the metals in batteries pose a significant risk of soil and water contamination.
*Government Support Measures for Activating a Future Waste Resource Circulation Ecosystem: Focusing on Batteries from End-of-Life Electric Vehicles" (KISTEP, February 8, 2023)
In conventional battery recycling, the typical method involves crushing spent batteries and extracting valuable metals such as lithium, nickel, and cobalt through chemical processes. However, this process requires high-concentration chemicals, which generate wastewater, and it demands substantial energy consumption due to the need for high-temperature furnaces that contribute significantly to carbon dioxide emissions.
To address these issues, direct recycling technology, which recovers and restores original materials without chemical alteration, has been attracting growing interest. However, direct recycling also has drawbacks, as it requires high-temperature and high-pressure conditions and involves complex procedures, making it both time-consuming and costly.
The research team has developed a novel technology for directly recycling spent cathode materials from lithium-ion batteries through a simple process that addresses the limitations of conventional recycling methods. This innovative approach restores the spent cathode to its original state by immersing it in a restoration solution under ambient temperature and pressure, effectively replenishing lithium ions.
The key technology is the application of galvanic corrosion using a restoration solution. Galvanic corrosion occurs when two dissimilar materials are in contact within an electrolyte environment, leading to the selective corrosion of one metal to protect the other. By utilizing this sacrificial mechanism, the research team has innovatively adapted this phenomenon for application in battery recycling.
The bromine in the restoration solution initiates spontaneous corrosion upon contact with the aluminum in the spent battery. During this process, electrons are released from the corroded aluminum and subsequently transferred to the spent cathode material. To maintain charge neutrality, lithium ions in the restoration solution are inserted into the cathode material. This recovery of lithium ions restores the cathode material to its original state.
Additionally, unlike conventional methods that require disassembly of the spent battery, the restoration reaction takes place directly within the cell, significantly enhancing the efficiency of the recycling process.
The research team confirmed through electrochemical performance testing that the restored cathode achieved a capacity equivalent to that of new materials.
Dr. Jung-Je Woo, the senior researcher, stated, “This research introduces a novel approach to restoring spent cathode materials without the need for high-temperature heat treatment or harmful chemicals.” He further emphasized, “The direct recycling of discarded electric vehicle batteries holds great potential for significantly reducing carbon emissions and establishing a circular resource economy.”
The team’s research results were published online in October 2024 in Advanced Energy Materials (Impact Factor 24.4, top 2.9%), a highly esteemed journal in the field of energy and materials science.
Journal
Advanced Energy Materials
DOI
10.1002/aenm.202402106
Article Title
Reviving Spent NCM Cathodes via Spontaneous Galvanic Corrosion in Ambient Atmospheric Condition
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