Postdoctoral position in NMR of polymer ionic liquid electrolytes for energy storage at UCSB (Santa Barbara, USA)
The postdoctoral research position is based at the Materials Department, University of California Santa Barbara (UCSB), in the group of Prof. Raphaële Clément. The position is available from January, 1st, 2019, and comes with an initial one-year contract.
Project Description
The research program focuses on the study of polymer ionic liquids (PILs), used as electrolytes in Li-ion rechargeable batteries, with solid-state NMR techniques. The postdoc will be working in close collaboration with the group of Prof. Segalman at UCSB, in charge of the synthesis of the PILs.
Li-ion batteries are the technology of choice for numerous applications, yet the energy density and safety of commercial devices is often limited by using organic liquid electrolytes with high flammability and poor stability of electrode/electrolyte interfaces during operation. Ionic liquids are a class of functional liquid salts that address both voltage and thermal stability concerns [1]. Incorporation of ionic liquid moieties onto a polymer to form PILs synergistically combines the functionality of ionic liquids with the mechanical robustness of the polymer backbone, an important criterion for lithium metal batteries. Unfortunately, polymer electrolytes generally exhibit low ionic conductivity due to a fundamental trade-off between improved mechanical properties and ion mobility [2]. Thus, an understanding of promising systems that would enable a decoupling of polymer mechanics from ion transport would be beneficial towards the targeted design of novel polymer electrolytes with good mechanical properties and high ionic conductivity.
The postdoc will investigate the Li+ transport properties of several PIL compositions using 7Li pulsed field gradient (PFG) NMR to determine the Li self-diffusion coefficient on the macroscopic (1-2 mm) lengthscale, as well as NMR relaxometry to characterize ionic conductivity at the microscopic scale. In addition, NMR will be used to investigate Li-Li site exchange [3] and Li-ligand binding kinetics [4]. NMR measurements will be correlated with conductivity measurements obtained via AC impedance techniques.
Relevant publications
[1] B. Garcia, S. Lavalle, G. Perron, C. Michot, and M. Armand, Room temperature molten salts as lithium battery electrolyte, Electrochim. Acta 49 (2004) 4583–4588. DOI: 10.1016/j.electacta.2004.04.041
[2] J. R. Sangoro, C. Iacob, A. L. Agapov, Y. Wang, S. Berdzinski, H. Rexhausen, V. Strehmel, C. Friedrich, A. P. Sokolov, and F. Kremer, Decoupling of ionic conductivity from structural dynamics in polymerized ionic liquids, Soft Matter 10 (2014) 3536–3540.
DOI: 10.1039/C3SM53202J
[3] M. N. d’Eurydice, E. T. Montrazi, C. A. Fortulan and T. J. Bonagamba, T2-tiltered T2-T2 Exchange NMR. J. Chem. Phys. 144 (2016) 204201. DOI: 10.1063/1.4951712
[4] Tan-Vu Huynh. NMR study of lithium mobility in polymer electrolytes. Ph.D. thesis. Université d’Orléans, 2015. English.
Requirements and Preferred Experience
The requirements for the position are a Ph.D. in Chemistry, Materials Science, Physics or Engineering, and experience with PFG-NMR and standard 2D solid-state NMR techniques. In addition to performing research, the postdoc will be expected to provide assistance with the training of graduate and undergraduate students in the group.
The Magnetic Resonance Facilities at UCSB
The spectroscopy facility of the Materials Research Laboratory at UCSB (see https://www.mrl.ucsb.edu/spectroscopy-facility/instruments) comprises several solid-state NMR spectrometers, including a 300 MHz system equipped with a MRI/diffusion probe, a 400 MHz DNP-NMR spectrometer, and 500 MHz and 800 MHz systems.
Additional Information
Interested candidates should send a cover letter, a résumé (including a list of publications), and the names and email addresses of at least two references to rclement@ucsb.edu.
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Raphaële Clément
Assistant Professor, Materials Department
Materials Research Laboratory, Room 3009
University of California, Santa Barbara, CA 93106-5121
Phone: 805-893-4294
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