(Press-News.org) RICHLAND, Wash. – Electric vehicles could travel farther and more renewable energy could be stored with lithium-sulfur batteries that use a unique powdery nanomaterial.
Researchers added the powder, a kind of nanomaterial called a metal organic framework, to the battery's cathode to capture problematic polysulfides that usually cause lithium-sulfur batteries to fail after a few charges. A paper describing the material and its performance was published online April 4 in the American Chemical Society journal Nano Letters.
"Lithium-sulfur batteries have the potential to power tomorrow's electric vehicles, but they need to last longer after each charge and be able to be repeatedly recharged," said materials chemist Jie Xiao of the Department of Energy's Pacific Northwest National Laboratory. "Our metal organic framework may offer a new way to make that happen."
Today's electric vehicles are typically powered by lithium-ion batteries. But the chemistry of lithium-ion batteries limits how much energy they can store. As a result, electric vehicle drivers are often anxious about how far they can go before needing to charge. One promising solution is the lithium-sulfur battery, which can hold as much as four times more energy per mass than lithium-ion batteries. This would enable electric vehicles to drive farther on a single charge, as well as help store more renewable energy. The down side of lithium-sulfur batteries, however, is they have a much shorter lifespan because they can't currently be charged as many times as lithium-ion batteries.
Energy Storage 101
The reason can be found in how batteries work. Most batteries have two electrodes: one is positively charged and called a cathode, while the second is negative and called an anode. Electricity is generated when electrons flow through a wire that connects the two. To control the electrons, positively charged atoms shuffle from one electrode to the other through another path: the electrolyte solution in which the electrodes sit.
The lithium-sulfur battery's main obstacles are unwanted side reactions that cut the battery's life short. The undesirable action starts on the battery's sulfur-containing cathode, which slowly disintegrates and forms molecules called polysulfides that dissolve into the liquid electrolyte. Some of the sulfur — an essential part of the battery's chemical reactions — never returns to the cathode. As a result, the cathode has less material to keep the reactions going and the battery quickly dies.
New materials for better batteries
Researchers worldwide are trying to improve materials for each battery component to increase the lifespan and mainstream use of lithium-sulfur batteries. For this research, Xiao and her colleagues honed in on the cathode to stop polysulfides from moving through the electrolyte.
Many materials with tiny holes have been examined to physically trap polysulfides inside the cathode. Metal organic frameworks are porous, but the added strength of PNNL's material is its ability to strongly attract the polysulfide molecules.
The framework's positively charged nickel center tightly binds the polysulfide molecules to the cathodes. The result is a coordinate covalent bond that, when combined with the framework's porous structure, causes the polysulfides to stay put.
"The MOF's highly porous structure is a plus that further holds the polysulfide tight and makes it stay within the cathode," said PNNL electrochemist Jianming Zheng.
Nanomaterial is key
Metal organic frameworks — also called MOFs — are crystal-like compounds made of metal clusters connected to organic molecules, or linkers. Together, the clusters and linkers assemble into porous 3-D structures. MOFs can contain a number of different elements. PNNL researchers chose the transition metal nickel as the central element for this particular MOF because of its strong ability to interact with sulfur.
During lab tests, a lithium-sulfur battery with PNNL's MOF cathode maintained 89 percent of its initial power capacity after 100 charge-and discharge cycles. Having shown the effectiveness of their MOF cathode, PNNL researchers now plan to further improve the cathode's mixture of materials so it can hold more energy. The team also needs to develop a larger prototype and test it for longer periods of time to evaluate the cathode's performance for real-world, large-scale applications.
PNNL is also using MOFs in energy-efficient adsorption chillers and to develop new catalysts to speed up chemical reactions.
"MOFs are probably best known for capturing gases such as carbon dioxide," Xiao said. "This study opens up lithium-sulfur batteries as a new and promising field for the nanomaterial."
This research was funded by the Department of Energy's Office of Energy Efficiency and Renewable Energy. Researchers analyzed chemical interactions on the MOF cathode with instruments at EMSL, DOE's Environmental Molecular Sciences Laboratory at PNNL.
In January, a Nature Communications paper by Xiao and some of her PNNL colleagues described another possible solution for lithium-sulfur batteries: developing a hybrid anode that uses a graphite shield to block polysulfides.
Reference: Jianming Zheng, Jian Tian, Dangxin Wu, Meng Gu, Wu Xu, Chongmin Wang, Fei Gao, Mark H. Engelhard, Ji-Guang Zhang, Jun Liu & Jie Xiao, "Lewis Acid-Base Interactions Between Polysulfides and Metal Organic Framework in Lithium Sulfur Batteries," Nano Letters, published online April 4, 2014, DOI: 10.1021/nl404721h.
Interdisciplinary teams at Pacific Northwest National Laboratory address many of America's most pressing issues in energy, the environment and national security through advances in basic and applied science. Founded in 1965, PNNL employs 4,300 staff and has an annual budget of about $950 million. It is managed by Battelle for the U.S. Department of Energy. For more information, visit the PNNL News Center, or follow PNNL on Facebook, Google+, LinkedIn and Twitter.
EMSL, the Environmental Molecular Sciences Laboratory, is a national scientific user facility sponsored by the Department of Energy's Office of Science. Located at Pacific Northwest National Laboratory in Richland, Wash., EMSL offers an open, collaborative environment for scientific discovery to researchers around the world. Its integrated computational and experimental resources enable researchers to realize important scientific insights and create new technologies. Follow EMSL on Facebook, LinkedIn and Twitter.
Relieving electric vehicle range anxiety with improved batteries
Lithium-sulfur batteries last longer with nanomaterial-packed cathode
ELSE PRESS RELEASES FROM THIS DATE:
Breakthrough points to new drugs from nature
Researchers at Griffith University's Eskitis Institute have developed a new technique for discovering natural compounds which could form the basis of novel therapeutic drugs. The corresponding author, Professor Ronald Quinn AM said testing the new process on a marine sponge had delivered not only confirmation that the system is effective, but also a potential lead in the fight against Parkinson's disease. "We have found a new screening method which allows us to identify novel molecules drawn from nature to test for biological activity," Professor Quinn said. "As it ...
Global scientific team 'visualizes' a new crystallization process
VIDEO: This is a high speed video of the crystal ribbons forming as the solution is spread using a squeegee like technique. Click here for more information. Sometimes engineers invent something before they fully comprehend why it works. To understand the "why," they must often create new tools and techniques in a virtuous cycle that improves the original invention while also advancing basic scientific knowledge. Such was the case about two years ago, when Stanford engineers ...
Researchers propose network-based evaluation tool to assess relief operations feasibility
The United Nations Office for Disaster Risk Reduction reported that disasters have affected around 2.9 billion people worldwide from 2000-2012— killing more than a million, and damaging around 1.7 trillion US dollars in estimates. Moreover, natural disasters and their damages have been documented to occur with increasing intensity. Given the staggering numbers, effective disaster preparedness and relief response plans is compelling, especially considering the fact that natural disasters are usually unpredictable and damage cannot be avoided. Implementing a speedy and ...
Medieval slave trade routes in Eastern Europe extended from Finland and the Baltic Countries to Asia
The routes of slave trade in Eastern Europe in the medieval and pre-modern period extended all the way to the Caspian Sea and Central Asia. A recent study completed at the University of Eastern Finland suggests that persons captured during raids into areas which today constitute parts of Finland, the Russian Karelia and the Baltic Countries ended up being sold on these remote trade routes. There was a particular demand for blonde girls and boys who were seen as exotic luxury items, and it was financially beneficial to transport them to the far-away markets. The study by ...
Study provides new insight into how toddlers learn verbs
Parents can help toddlers' language skills by showing them a variety of examples of different actions, according to new research from the University of Liverpool. Previous research has shown that verbs pose particular difficulties to toddlers as they refer to actions rather than objects, and actions are often different each time a child sees them. To find out more about this area of child language, University psychologists asked a group of toddlers to watch one of two short videos. They then examined whether watching a cartoon star repeat the same action, compared ...
Potential use of Google Glass in surgical settings
Oxford, UK, April 15, 2014 – An article recently published in the International Journal of Surgery shows the potential applications for Google Glass in the surgical setting, particularly in relation to training. Personal portable information technology is advancing at a breathtaking speed. Google has recently introduced Glass, a device that is worn like conventional glasses, but that combines a computerized central processing unit, touchpad, display screen, high-definition camera, microphone, bone-conduction transducer, and wireless connectivity. The authors of the ...
Multiple births don't have to be an inevitable result of fertility treatments
While fertility treatments have helped many people become parents, they commonly result in multiple births, increasing the risk of prematurity, and leading to lifelong complications. But this doesn't have to be the case, according to Yale School of Medicine researchers and their colleagues, who recommend sweeping changes to policy and clinical practice in a study published in the April issue of Fertility & Sterility. Pasquale Patrizio, M.D., professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine, and his colleagues at ...
Ant colonies help evacuees in disaster zones
An escape route mapping system based on the behavior of ant colonies could give evacuees a better chance of reaching safe harbor after a natural disaster or terrorist attack by building a map of showing the shortest routes to shelters and providing regular updates of current situations such as fires, blocked roads or other damage via the smart phones of emergency workers and those caught up in the disaster. Koichi Asakura of Daido University in Nagoya and Toyohide Watanabe of the Nagoya Industrial Science Research Institute in Japan have carried out successful simulations ...
New Geosphere series: The St. Elias Erosion/Tectonics Project in Southern Alaska
Boulder, Colo., USA – GEOSPHERE has added a new themed issue to its roster: "Neogene tectonics and climate-tectonic interactions in the southern Alaskan orogeny." Interest in Alaskan tectonics has varied over time, propelled mostly by geologic hazards. In 1964, the great Alaskan earthquake focused attention on Alaska and was a major factor in the establishment of the concept of subduction in the early days of plate tectonics. In the 1980s, the northern Cordillera, including Alaska, was the subject of extensive study using the terrane analysis approach, which spawned ...
Diverse gene pool critical for tigers' survival, say Stanford scholars
New research by Stanford scholars shows that increasing genetic diversity among the 3,000 or so tigers left on the planet is the key to their survival as a species. Iconic symbols of power and beauty, wild tigers may roam only in stories someday soon. Their historical range has been reduced by more than 90 percent. But conservation plans that focus only on increasing numbers and preserving distinct subspecies ignore genetic diversity, according to the study. In fact, under that approach, the tiger could vanish entirely. "Numbers don't tell the entire story," said study ...
LAST 30 PRESS RELEASES:
Scientists model 'true prevalence' of COVID-19 throughout pandemic
New breakthrough to help immune systems in the fight against cancer
Through the thin-film glass, researchers spot a new liquid phase
Administering opioids to pregnant mice alters behavior and gene expression in offspring
Brain's 'memory center' needed to recognize image sequences but not single sights
Safety of second dose of mRNA COVID-19 vaccines after first-dose allergic reactions
Changes in disparities in access to care, health after Medicare eligibility
Use of high-risk medications among lonely older adults
65+ and lonely? Don't talk to your doctor about another prescription
Exosome formulation developed to deliver antibodies for choroidal neovascularization therapy
Second COVID-19 mRNA vaccine dose found safe following allergic reactions to first dose
Plant root-associated bacteria preferentially colonize their native host-plant roots
Rare inherited variants in previously unsuspected genes may confer significant risk for autism
International experts call for a unified public health response to NAFLD and NASH epidemic
International collaboration of scientists rewrite the rulebook of flowering plant genetics
Improving air quality reduces dementia risk, multiple studies suggest
Misplaced trust: When trust in science fosters pseudoscience
Two types of blood pressure meds prevent heart events equally, but side effects differ
New statement provides path to include ethnicity, ancestry, race in genomic research
Among effective antihypertensive drugs, less popular choice is slightly safer
Juicy past of favorite Okinawan fruit revealed
Anticipate a resurgence of respiratory viruses in young children
Anxiety, depression, burnout rising as college students prepare to return to campus
Goal-setting and positive parent-child relationships reduce risk of youth vaping
New research identifies cancer types with little survival improvements in adolescents and young adul
Oncotarget: Replication-stress sensitivity in breast cancer cells
Oncotarget: TERT and its binding protein: overexpression of GABPA/B in gliomas
Development of a novel technology to check body temperature with smartphone camera
The mechanics of puncture finally explained
Extreme heat, dry summers main cause of tree death in Colorado's subalpine forests[Press-News.org] Relieving electric vehicle range anxiety with improved batteries
Lithium-sulfur batteries last longer with nanomaterial-packed cathode