The electric vehicle market continues to build momentum every year, with consumers around the world growing more interested. But in order for EVs to pave the way for the future of transportation, more efficient, longer-lasting batteries will need to be developed.
The consumer demand for seamless, integrated technology is on the rise, and with it grows the Internet of Things, which is expected to grow to a multitrillion-dollar market by 2020. But in order to develop a fully integrated electronic network, flexible, lightweight, rechargeable power sources will be required.
A team of researchers from Ulsan National Institute of Science and Technology is looking to address that issue, developing inkjet-printed batteries that can be modified to fit devices of any shape and size. The team reports that the newly developed inks can be printed onto paper to create a new class of printed supercapacitors.
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This from Ulsan National Institute of Science and Technology:
The process involves using a conventional inkjet printer to print a preparatory coating—a ‘wood cellulose-based nanomat’—onto a normal piece of A4 paper. Next, an ink of activated carbon and single-walled nanotubes is printed onto the nanomat, followed by an ink made of silver nanowires in water. These two inks form the electrodes. Finally, an electrolyte ink—formed of an ionic liquid mixed with a polymer that changes its properties when exposed to ultraviolet light—is printed on top of the electrodes. The inks are exposed at various stages to ultraviolet irradiation and finally the whole assembly is sealed onto the piece of paper with an adhesive film.
Lithium-ion batteries power a vast majority of the world’s portable electronics, but the magnification of recent safety incidents have some looking for new ways to keep battery-related hazards at bay. The U.S. Navy is one of those groups, with chemists in the U.S. Naval Research Laboratory (NRL) unveiling a new battery, which they say is both safe and rechargeable for applications such as electric vehicles and ships.
“We keep having too many catastrophic news stories of lithium-ion batteries smoking, catching fire, exploding,” says Debra Rolison, head of NRL’s advanced electrochemical materials section and co-author of the recently published paper. “There’ve been military platforms that have suffered severe damage because of lithium-ion battery fires.”
Once example of such damage came in 2008, when an explosion and fire caused by a lithium-ion battery damaged the Advanced SEAL Delivery Vehicle 1 at its base in Pearl Harbor.
While generally safe when manufactured properly, lithium-ion batteries host an organic liquid which is flammable if the battery or device gets too hot.
Like all things, batteries have a finite lifespan. As batteries get older and efficiency decreases, they enter what researchers call “capacity fade,” which occurs when the amount of charge your battery could once hold begins to decrease with repeated use.
But what if researchers could reduce this capacity fade?
That’s what researchers from Argonne National Laboratory are aiming to do, as demonstrated in their open access paper, “Transition Metal Dissolution, Ion Migration, Electrocatalytic Reduction and Capacity Loss in Lithium-Ion Full Cells,” which was recently published in the Journal of The Electrochemical Society.
The capacity of a lithium-ion battery directly correlates to the amount of lithium ions that can be shuttled back and forth as the device is charged and discharged. Transition metal ions make this shuttling possible, but as the battery is cycled, some of those ions get stripped out of the cathode material and end up at the battery’s anode.
Researchers from Columbia University School of Engineering and Applied Science recently developed a method that could result in safer, longer-lasting, bendable lithium-ion batteries. To do this, the team applied ice-templating to control the structure of the solid electrolyte for lithium-ion batteries.
Recent reports of cell phones and hoverboards bursting into flames have made people aware of the safety concerns related to the lithium-ion battery’s liquid electrolyte. The researchers behind this new work decided to confront the safety issues by exploring the use of a solid electrolyte, therefore developing an all-solid-state lithium battery.
[The researchers] were interested in using ice-templating to fabricate vertically aligned structures of ceramic solid electrolytes, which provide fast lithium ion pathways and are highly conductive. They cooled the aqueous solution with ceramic particles from the bottom and then let ice grow and push away and concentrate the ceramic particles. They then applied a vacuum to transition the solid ice to a gas, leaving a vertically aligned structure. Finally, they combined this ceramic structure with polymer to provide mechanical support and flexibility to the electrolyte.
A team of scientists from Oak Ridge National Laboratory is using the precision of an electron beam to instantly adhere cathode coatings for lithium-ion batteries. This new development, as reported in the Journal of The Electrochemical Society, could lead to a leap in efficiency that saves energy, reduces production cost, and eliminates the use of toxic solvents.
This from ORNL:
The technique uses an electron beam to cure coating material as it rolls down the production line, creating instantaneous cross-links between molecules that bind the coating to a foil substrate, without the need for solvents, in less than a second.
“Typical curing processes can require drying machinery the length of a football field and expensive equipment for solvent recovery,” says David Wood, co-author of the study. “This approach presents a promising avenue for fast, energy-efficient manufacturing of high-performance, low-cost lithium-ion batteries.”
Read the full paper, “Electron Beam Curing of Composite Positive Electrode for Li-Ion Battery.”
Joint research from the Universidad Carlos III de Madrid and the Council for Scientific Research reports the development of a new ceramic electrode for lithium-ion batteries that can lead to cheaper, more efficient, and safer conventional batteries.
“What we have patented are new ceramic electrodes that are much safer and can work in a wider temperature interval,” says Alejandro Varez, co-author of the research.
To achieve this result, the researchers made ceramic sheets by way of thermoplastic extrusion molds.
“This technique allows making electrodes that are flat or tube-shaped, and these electrodes can be applied to any type of lithium-ion battery,” Varez says.
According to the researchers, the cost of production is low and it could easily be adapted into current lithium-ion battery production, making this an easy technology to move quickly to industrialization.
Reports of a woman’s headphones catching fire while on a flight from Bejing to Melbourne has once again heightened interest in lithium-ion battery safety. According to the Australian Transport Safety Bureau, the incident occurred while the woman was sleeping mid-flight wearing battery-powered headphones.
Early in 2016, battery expert and ECS fellow, K.M. Abraham, talked to ECS about lithium-ion battery safety concerns amidst reports of exploding hoverboards. Below are some excerpts of what he had to say.
“It is safe to say that these well-publicized hazardous events are rooted in the uncontrolled release of the large amount of energy stored in lithium-ion batteries as a result of manufacturing defects, inferior active and inactive materials used to build cells and battery packs, substandard manufacturing and quality control practices by a small fraction of cell manufacturers, and user abuses of overcharge and over-discharge, short-circuit, external thermal shocks and violent mechanical impacts,” Abraham told ECS. “All of these mistreatments can lead lithium-ion batteries to thermal runaway reactions accompanied by the release of hot combustible organic solvents which catch fire upon contact with oxygen in the atmosphere.”
Taking a detailed look inside energy storage systems could help solve potential issues before they arise. A team of researchers from Brookhaven National Laboratory are doing just that by imaging the inner workings of a sodium-metal sulfide battery, leading them to understand the cause of degraded performance.
“We discovered that the loss in battery capacity is largely the result of sodium ions entering and leaving iron sulfide—the battery electrode material we studied—during the first charge/discharge cycle,” says Jun Wang, co-author of the study. “The electrochemical reactions involved cause irreversible changes in the microstructure and chemical composition of iron sulfide, which has a high theoretical energy density. By identifying the underlying mechanism limiting its performance, we seek to improve its real energy density.”
Performance degradation in charge/discharge cycles has been the main problem researchers encounter when pursuing sodium-ion battery research. While the battery’s performance points to degradation issues, not much was previously known about what caused this degradation.
In June 2016, the International Meeting on Lithium Batteries (IMLB) in Chicago successfully celebrated 25 years of the commercialization of lithium-ion batteries. According to Doron Aurbach, technical editor of the Batteries and Energy Storage topical interest area of the Journal of The Electrochemical Society, research efforts in the Li-battery community continues to provide ground-breaking technological success in electromobility and grid storage applications. He hopes this research will continue to revolutionize mobile energy supply for future advances in ground transportation.
ECS has published 66 papers for a new IMLB focus issue in the Journal of The Electrochemical Society. All papers are open access at no charge to the authors and no charge to download thanks to ECS’s Free the Science initiative!
The focus issue provides important information on the forefront of advanced battery research that appropriately reflects the findings from the symposium.
