BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//7.2.3.1//EN TZID:America/New_York X-WR-TIMEZONE:America/New_York BEGIN:VEVENT UID:0-5639@eng.ufl.edu DTSTART;TZID=America/New_York:20230328T091500 DTEND;TZID=America/New_York:20230328T101500 DTSTAMP:20251201T182521Z URL:https://www.eng.ufl.edu/news-events/events/che-seminar-ion-transport-i n-charged-polymer-electrolytes-the-pursuit-of-high-li-transference-number/ SUMMARY:ChE Seminar: Ion transport in charged polymer electrolytes: the pur suit of high Li+ transference number DESCRIPTION:Bryan D. McCloskey\, Ph.D.\nChair of Chemical and Biomolecular Engineering\nThe Warren and Katharine Schlinger Distinguished Professor in Chemical Engineering\nChemical &\; Biomolecular Engineering\nUniversit y of California\, Berkeley\nEnergy Storage and Distributed Resources Divis ion\, Lawrence Berkeley National Laboratory\nTitle: Ion transport in charg ed polymer electrolytes: the pursuit of high Li+ transference number\nAbst ract: Conventional Li-ion battery electrolytes have been designed to optim ize numerous desirable properties\, including interfacial and thermal stab ility\, conductivity\, and low flammability. However\, all Li+-bearing ele ctrolytes still possess low Li+ transference (t+) numbers\, where current passed through them is primarily carried by the counteranion\, resulting i n large concentration gradients that limit battery performance\, particula rly at high discharge and charging rates. The development of high t+ elect rolytes—those in which most (or all) current is carried by the Li+ ion —could enable safer battery cycling\, faster charging rates\, and thicke r\, more energy-dense cathode designs in Li-ion batteries.\nThis presentat ion will outline our attempts to develop polymer-based high t+ electrolyte s wherein anions are appended to a polymer (polyanions) and neutralized wi th Li ions. In this configuration\, Li ions\, when appropriately solvated\ , have hydrodynamic radii much smaller than the polymer’s radius of gyra tion\, ostensibly allowing them to diffuse or migrate faster than their ap pended counteranions\, and hence enable high t+ electrolytes. Ultimately\, I show this picture to be oversimplified\, and that anion-anion and catio n-anion correlations severely limit the t+ of high conductivity polyanioni c solutions.\nInitially\, I will present studies that highlight the inhere nt tradeoff between segmental motion and ion content that has generally li mited room temperature conductivity of dry polymer electrolyte systems. We show that blending of a small molecule diluent breaks the apparent tradeo ff between segmental dynamics and charge carrier concentration in dry poly mer electrolytes\, motivating the pursuit of polyelectrolyte solutions (ch arged polymers dissolved in solvent) as potential high t+ electrolytes. In the second part of the presentation\, I discuss our efforts to understand and characterize the full transport properties of a model\, monodisperse\ , battery-relevant oligomeric polyelectrolyte system. Intriguingly\, for p olyelectrolytes with larger molecular weights\, we observe that the averag e velocity of Li ions in an electric field is in the direction opposite th an expected\, evidence of a negative t+ due to correlated motion through L i ion condensation on the polyelectrolyte chain. While this result is a ne gative outcome in our pursuit of high t+ electrolytes\, we anticipate many of the capabilities and insights gleaned throughout our studies to be of general use to those studying novel\, concentrated electrolyte solutions w here strong\, non-ideal ion-ion correlations are observed.\nBio: Bryan McC loskey is the Department Chair and Warren &\; Katharine Schlinger Disti nguished Professor in Chemical Engineering in the Department of Chemical a nd Biomolecular Engineering at the University of California\, Berkeley. He also holds a joint appointment as a Faculty Engineer in the Energy Storag e and Distributed Resources Division at Lawrence Berkeley National Laborat ory. His laboratory explores numerous applications of electrochemistry to energy sustainability\, conversion\, and storage. Current projects focus o n electrochemical regeneration of alkaline sorbents for direct air CO2 cap ture\, elucidating the fundamental electrochemistry of metal-air batteries \, and understanding a variety of challenges facing Li-ion batteries\, inc luding high voltage cathode stability\, advanced cathode material developm ent (Ni-rich and Li- rich NMC oxides and Li-excess disordered rocksalt mat erials)\, extreme fast charging\, and low temperature and high transferenc e number electrolyte formulations. He has co-authored 150 articles and has won numerous awards for his research\, including The Electrochemical Soci ety Charles Tobias Award\, The International Society of Electrochemistry T ajima Prize\, and the VW/BASF Science Award- Electrochemistry. More inform ation about the McCloskey Lab can be found at the Lab’s website: www.mcc loskeylab.com CATEGORIES:Seminars LOCATION:Room 201\, Engineering Building (NEB)\, 1064 Center Drive\, Gaine sville \, FL\, 32611\, United States X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS= 1064 Center Drive\, Gaines ville \, FL\, 32611\, United States;X-APPLE-RADIUS=100;X-TITLE=Room 201\, Engineering Building (NEB):geo:0,0 END:VEVENT BEGIN:VTIMEZONE TZID:America/New_York X-LIC-LOCATION:America/New_York BEGIN:DAYLIGHT DTSTART:20230312T030000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:EDT END:DAYLIGHT END:VTIMEZONE END:VCALENDAR