chemistry

UK-MRS Seminars

UK-MRS Seminars

June 12. 2017, 10:00-11:00 am

C226 OHR (Oliver H. Raymond Civil Engineering Building)

 

“Anode Surface Evolution in Aqueous Sodium-Ion Batteries”

Xiaowen Zhan, Department of Chemical and Materials Engineering 

Aqueous sodium-ion batteries may solve the cost and safety issues associated with the energy storage systems for the fluctuating supply of electricity based on solar and wind power. Compared to their lithium counterparts, aqueous sodium-ion batteries offer multiple advantages including more earth abundant sodium, cheaper electrode materials and electrolyte solutions as well as less costly manufacturing conditions. However, poor overall performance and low electrode utilization (much of the electrode material ends up being electrochemically inactive) are the main barriers implementing them in (micro) grid systems. Here we characterize the surface reactions on NASICON-type phosphate anode materials and rationalize their close associations with capacity fading upon slow cycling of aqueous sodium-ion batteries. The surface reactions result in the formation of an electrically insulating surface layer causing the failure of electrochemical performance and the precipitation of surface particles that blocks the pores thereby leading to poor electrode utilization. These findings provide insights into new possibilities of improving the electrochemical performance of aqueous sodium-ion batteries by designing protective layers through surface modifications that prevent the formation of insulating surface layers and insoluble precipitates. 

 

“Stable, High-Capacity Electrolytes for Non-Aqueous Redox Flow Batteries”

Harsha Attanayake, Department of Chemistry University of Kentucky

Redox flow batteries (RFBs) are one of the promising electrochemical devices for stationary energy storage applications due to their decoupled energy and power, long service life, and simple manufacturing. Despite advances of commercially available aqueous RFBs, they suffer from lower energy densities due to narrow electrochemical window of water (~1.5 V). Transitioning from aqueous to non-aqueous chemistry offers a wider and stable electrochemical window (>4 V), a greater selection of redox materials, a wider range of working temperatures, high cell voltage, and potentially high energy density. So far, only a limited number of highly soluble and stable organic compounds have been reported for non- aq RFBs applications as catholytes. It is crucial that the design of organic electro-active materials does not compromise any of the following characteristics: high solubility (charged and neutral states), higher oxidation potential (for electron donors), and enabling a high molecular capacity for electron donation (or acceptance). Our studies mainly focus on development of high capacity catholytes for non-aqueous redox flow batteries with stable neutral and oxidized states. This presentation will focus on molecular designing strategies to increase the solubility of phenothiazine derivatives in their charged states and neutral states, stabilization of one and two electron donation, and a new approach to raise the oxidation potential, along with their synthesis and electrochemical analysis. 

 

 

 

Date: 
Monday, June 12, 2017 - 10:00am to 11:00am
Location: 
OHR C226

Expanding Your Horizons Introduces Middle School Girls to STEM

Middle school students are awed when they get the chance to turn a banana into a percussion instrument at the 2017 Expanding Your Horizons STEM workshop for girls.

Guiton, Odom, and Anthony Receive NASA Kentucky Funding for Research Infrastructure Development

Two NASA Kentucky grants were awarded to support research in the Chemistry Department. Prof. Beth Guiton received funding for using single-atom resolution and in situ Imaging to determine the structure of thermoelectric materials in real-time. Profs. Susan Odom and John Anthony received funding for the development of a low temperature redox flow battery prototype for space applications.

Pillar and Guzman reveal how aromatic pollutants emitted during combustion and wood burning contribute to the formation of brown clouds

Aerosol particles suspended in the air of urban environments typically reduce visibility, interact with sunlight by scattering and absorbing radiation, and lower air quality. In addition, these tiny particles can also contribute large pollution plumes, called “brown clouds”, which have been observed to originate over South Asia in recent years and undergo long distance transport by the wind to reach other continents. The particles in brown clouds are composed by an unhealthy and variable mix including ozone and organic molecules found in smoke.

Undergraduate Student Honored by the Division of Environmental Chemistry of the American Chemical Society

In recognition of his contributions to the field of environmental chemistry Kayvon Ghayoumi is honored with the Division of Environmental Chemistry 2017 Undergraduate award from the American Chemical Society. Ghayoumi earned a B.A. in Chemistry at the University of Kentucky this Spring. His interest in Environmental Chemistry started while taking CHE 565 taught by Dr. Marcelo Guzman, who later became his research supervisor.

Chemistry Undergraduate and Graduate Students Recognized in Graduation & Awards Ceremony

At the Graduation Celebration & Student Awards Ceremony, held Friday, May 5, 2017, in the Jacobs Science Building, several undergraduate and graduate students were recognized.

 

Undergraduate Awards:

Freshman Chemistry Award: Jacqueline Kowalke

General Chemistry Excellence Award: Nathaniel Morgan, Grace Anderson

Hammond Leadership Award: Amir Kucharski

Hammond Undergraduate Service Award: Jumanah Mahmoud

William Meredith Riggs Award: Aaron Snell

Nancy J. Stafford Award: Sarah Gobel

Bin Sun selected to attend workshop on Computational Physiology of Excitable Tissues

Bin Sun was selected as one of fifteen recipients of an all-expense-paid workshop on the Computational Physiology of Excitable Tissues. The workshop meets for two weeks in Oslo, followed by another two weeks in San Diego. Bin is a graduate student in the research group of Prof.

Blue, Kekenes-Huskey, Miller, and Odom Recognized in College of Arts & Sciences Awards Ceremony

For faculty members from the Chemistry Department received recognition for awards received from the College of Arts and Sciences for their efforts in teaching, mentoring, outreach, and service in an  Faculty Awards Ceremony to recognize their accomplishments on Tuesday, April 25 at 3:30 pm in the W.T. Young library auditorium. 

Eugene and Guzman reveal how sunlight can spark chemical reactions in clouds, fog, and mist

Atmospheric aerosols such as smoke, fog, and mist are made of fine solid or liquid particles suspended in air. In the lower atmosphere aerosols play a major role in controlling air quality, as well as in scattering and absorbing sunlight. This interaction of aerosols with light varies widely and depends on their complex chemical composition that rapidly changes under the governing highly reactive conditions found in the atmosphere. Importantly, the mysterious formation of carbon-containing atmospheric particles has intrigued atmospheric scientists during the last decade.

Glazer research group's work highlighted on the back cover of the European Journal of Inorganic Chemistry

A research study performed by Dr. Dmytro Havrylyuk, Dr. David Heidary, Leona Nease, Dr. Sean Parkin, and Dr. Edith Glazer was profiled on the back cover of the journal The European Journal of Inorganic Chemistry for a special cluster issue titled "Metal Anticancer Complexes – Activity, Mechanism of Action and Future Perspectives". 

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