Entity

Time filter

Source Type


Harutyunyan A.R.,Materials Science Division
33rd Annual International Battery Seminar and Exhibit: Advanced Battery Technologies for Consumer, Automotive and Military Applications | Year: 2016

Single wall carbon nanotubes are excellent conductive additives for battery electrodes. Source


News Article
Site: http://www.rdmag.com/rss-feeds/all/rss.xml/all

Lawrence Livermore National Laboratory researchers have created a library of nanoporous gold structures on a single chip that has direct applications for high-capacity lithium ion batteries as well as neural interfaces. Nanoporous gold (np-Au), a porous metal used in energy and biomedical research, is produced through an alloy corrosion process known as dealloying that generates a characteristic three-dimensional nanoscale network of pores and ligaments. In the cover article in the Jan. 14 issue of Nanoscale(link is external), a journal published by the Royal Society of Chemistry, LLNL researchers and their University of California, Davis(link is external) collaborators describe a method for creating a library of varying np-Au morphologies on a single chip via precise delivery of tunable laser energy. UC Davis professor Erkin Seker served as the principal investigator (PI) of the UC Fees project that primarily funded the work, along with co-PI Monika Biener of LLNL’s Materials Science Division. Laser microprocessing (e.g. micromachining) provides spatial and temporal control while imposing energy near the surface of the material. “Traditional heat application techniques for the modification of np-Au are bulk processes that cannot be used to generate a library of different pore sizes on a single chip,” said LLNL staff scientist Ibo Matthews, co-author of the paper. “Laser microprocessing offers an attractive solution to this problem by providing a means to apply energy with high spatial and temporal resolution.” The researchers used multiphysics simulations to predict the effects of continuous wave vs. pulsed laser mode and varying thermal conductivity of the supporting substrate on the local np-Au film temperatures during photothermal annealing. They were then able to fabricate an on-chip material library consisting of 81 np-Au samples of nine different morphologies for use in the parallel study of structure–property relationships. “These libraries have the potential to drastically increase the throughput of morphology interaction studies for np-Au, specifically in applications such as high capacity lithium ion batteries, cell-material interaction studies for neural interfaces, analytical biosensors, as well as nanoscale material science studies,” said Biener, co-author of the paper. This work sets the foundation for understanding laser-based annealing of porous thin film materials. The fabrication of single chip material libraries has the potential to increase the throughput of material interaction testing in many disciplines through easy single-chip material screening libraries. LLNL’s Juergen Biener of the Material Sciences Division collaborated on the work along with UC Davis researchers Christopher Chapman (lead author) and Ling Wang. This work was funded by UC Lab Fees, National Science Foundation and National Institutes of Health.


News Article
Site: http://www.cemag.us/rss-feeds/all/rss.xml/all

Lawrence Livermore National Laboratory researchers have created a library of nanoporous gold structures on a single chip that has direct applications for high-capacity lithium ion batteries as well as neural interfaces. Nanoporous gold (np-Au), a porous metal used in energy and biomedical research, is produced through an alloy corrosion process known as dealloying that generates a characteristic three-dimensional nanoscale network of pores and ligaments. In the cover article in a recent issue of Nanoscale, a journal published by the Royal Society of Chemistry, LLNL researchers and their University of California, Davis collaborators describe a method for creating a library of varying np-Au morphologies on a single chip via precise delivery of tunable laser energy. UC Davis professor Erkin Seker served as the principal investigator (PI) of the UC Fees project that primarily funded the work, along with co-PI Monika Biener of LLNL’s Materials Science Division. Laser microprocessing (e.g. micromachining) provides spatial and temporal control while imposing energy near the surface of the material. “Traditional heat application techniques for the modification of np-Au are bulk processes that cannot be used to generate a library of different pore sizes on a single chip,” says LLNL staff scientist Ibo Matthews, co-author of the paper. “Laser microprocessing offers an attractive solution to this problem by providing a means to apply energy with high spatial and temporal resolution.” The researchers used multiphysics simulations to predict the effects of continuous wave vs. pulsed laser mode and varying thermal conductivity of the supporting substrate on the local np-Au film temperatures during photothermal annealing. They were then able to fabricate an on-chip material library consisting of 81 np-Au samples of nine different morphologies for use in the parallel study of structure-property relationships. “These libraries have the potential to drastically increase the throughput of morphology interaction studies for np-Au, specifically in applications such as high capacity lithium ion batteries, cell-material interaction studies for neural interfaces, analytical biosensors, as well as nanoscale material science studies,” says Biener, co-author of the paper. This work sets the foundation for understanding laser-based annealing of porous thin film materials. The fabrication of single chip material libraries has the potential to increase the throughput of material interaction testing in many disciplines through easy single-chip material screening libraries. LLNL’s Juergen Biener of the Material Sciences Division collaborated on the work along with UC Davis researchers Christopher Chapman (lead author) and Ling Wang. This work was funded by UC Lab Fees, National Science Foundation, and National Institutes of Health. Release Date: January 20, 2016 Source: Lawrence Livermore National Laboratory


News Article
Site: http://www.materialstoday.com/news/

Lawrence Livermore National Laboratory scientists have found that lithium ion batteries operate longer and faster when their electrodes are treated with hydrogen. Lithium ion batteries (LIBs) are a class of rechargeable battery types in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. The growing demand for energy storage emphasizes the urgent need for higher-performance batteries. Several key characteristics of lithium ion battery performance -- capacity, voltage and energy density -- are ultimately determined by the binding between lithium ions and the electrode material. Subtle changes in the structure, chemistry and shape of an electrode can significantly affect how strongly lithium ions bond to it. Through experiments and calculations, the Livermore team discovered that hydrogen-treated graphene nanofoam electrodes in the LIBs show higher capacity and faster transport. “These findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes,” said Morris Wang, an LLNL materials scientist and co-author of a paper (link is external) appearing in Nov. 5 edition of Nature Scientific Reports. Lithium ion batteries are growing in popularity for electric vehicle and aerospace applications. For example, lithium ion batteries are becoming a common replacement for the lead acid batteries that have been used historically for golf carts and utility vehicles. Instead of heavy lead plates and acid electrolytes, the trend is to use lightweight lithium ion battery packs that can provide the same voltage as lead-acid batteries without requiring modification of the vehicle's drive system. Commercial applications of graphene materials for energy storage devices, including lithium ion batteries and supercapacitors, hinge critically on the ability to produce these materials in large quantities and at low cost. However, the chemical synthesis methods frequently used leave behind significant amounts of atomic hydrogen, whose effect on the electrochemical performance of graphene derivatives is difficult to determine. Yet Livermore scientists did just that. Their experiments and multiscale calculations reveal that deliberate low-temperature treatment of defect-rich graphene with hydrogen can actually improve rate capacity. Hydrogen interacts with the defects in the graphene and opens small gaps to facilitate easier lithium penetration, which improves the transport. Additional reversible capacity is provided by enhanced lithium binding near edges, where hydrogen is most likely to bind. “The performance improvement we’ve seen in the electrodes is a breakthrough that has real world applications,” said Jianchao Ye, who is a postdoc staff scientist at the Lab’s Materials Science Division, and the leading author of the paper. To study the involvement of hydrogen and hydrogenated defects in the lithium storage ability of graphene, the team applied various heat treatment conditions combined with hydrogen exposure and looked into the electrochemical performance of 3-D graphene nanofoam (GNF) electrodes, which are comprised chiefly of defective graphene. The team used 3-D graphene nanofoams due to their numerous potential applications, including hydrogen storage, catalysis, filtration, insulation, energy sorbents, capacitive desalination, supercapacitors and LIBs. The binder-free nature of graphene 3-D foam makes them ideal for mechanistic studies without the complications caused by additives. “We found a drastically improved rate capacity in graphene nanofoam electrodes after hydrogen treatment. By combining the experimental results with detailed simulations, we were able to trace the improvements to subtle interactions between defects and dissociated hydrogen. This results in some small changes to the graphene chemistry and morphology that turn out to have a surprisingly huge effect on performance,” said LLNL scientist Brandon Wood, another co-author of the paper. The research suggests that controlled hydrogen treatment may be used as a strategy for optimizing lithium transport and reversible storage in other graphene-based anode materials. This story is reprinted from material from Lawrence Livermore National Laboratory, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.


News Article
Site: http://www.nanotech-now.com/

Abstract: Lawrence Livermore National Laboratory scientists have found that lithium ion batteries operate longer and faster when their electrodes are treated with hydrogen. Lithium ion batteries (LIBs) are a class of rechargeable battery types in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. The growing demand for energy storage emphasizes the urgent need for higher-performance batteries. Several key characteristics of lithium ion battery performance -- capacity, voltage and energy density -- are ultimately determined by the binding between lithium ions and the electrode material. Subtle changes in the structure, chemistry and shape of an electrode can significantly affect how strongly lithium ions bond to it. Through experiments and calculations, the Livermore team discovered that hydrogen-treated graphene nanofoam electrodes in the LIBs show higher capacity and faster transport. "These findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes," said Morris Wang, an LLNL materials scientist and co-author of a paper appearing in Nov. 5 edition of Nature Scientific Reports. Lithium ion batteries are growing in popularity for electric vehicle and aerospace applications. For example, lithium ion batteries are becoming a common replacement for the lead acid batteries that have been used historically for golf carts and utility vehicles. Instead of heavy lead plates and acid electrolytes, the trend is to use lightweight lithium ion battery packs that can provide the same voltage as lead-acid batteries without requiring modification of the vehicle's drive system. Commercial applications of graphene materials for energy storage devices, including lithium ion batteries and supercapacitors, hinge critically on the ability to produce these materials in large quantities and at low cost. However, the chemical synthesis methods frequently used leave behind significant amounts of atomic hydrogen, whose effect on the electrochemical performance of graphene derivatives is difficult to determine. Yet Livermore scientists did just that. Their experiments and multiscale calculations reveal that deliberate low-temperature treatment of defect-rich graphene with hydrogen can actually improve rate capacity. Hydrogen interacts with the defects in the graphene and opens small gaps to facilitate easier lithium penetration, which improves the transport. Additional reversible capacity is provided by enhanced lithium binding near edges, where hydrogen is most likely to bind. "The performance improvement we've seen in the electrodes is a breakthrough that has real world applications," said Jianchao Ye, who is a postdoc staff scientist at the Lab's Materials Science Division, and the leading author of the paper. To study the involvement of hydrogen and hydrogenated defects in the lithium storage ability of graphene, the team applied various heat treatment conditions combined with hydrogen exposure and looked into the electrochemical performance of 3-D) graphene nanofoam (GNF) electrodes, which are comprised chiefly of defective graphene. The team used 3-D graphene nanofoams due to their numerous potential applications, including hydrogen storage, catalysis, filtration, insulation, energy sorbents, capacitive desalination, supercapacitors and LIBs. The binder-free nature of graphene 3D foam makes them ideal for mechanistic studies without the complications caused by additives. "We found a drastically improved rate capacity in graphene nanofoam electrodes after hydrogen treatment. By combining the experimental results with detailed simulations, we were able to trace the improvements to subtle interactions between defects and dissociated hydrogen. This results in some small changes to the graphene chemistry and morphology that turn out to have a surprisingly huge effect on performance," said LLNL scientist Brandon Wood, who directed the theory effort on the paper. The research suggests that controlled hydrogen treatment may be used as a strategy for optimizing lithium transport and reversible storage in other graphene-based anode materials. ### Other Livermore researchers include co-lead author Mitchell Ong, Tae Wook Heo, Patrick Campbell, Marcus Worsley, Yuanyue Liu, Swanee Shin, Supakit Charnvanichborikarn, Manyalibo Matthews, Michael Bagge-Hansen and Jonathan Lee. The work was funded by LLNL's Laboratory Directed Research and Development program. About Lawrence Livermore National Laboratory Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Discover hidden collaborations