Paul Rudnicki
Ph.D. Student in Chemical Engineering, admitted Autumn 2017
All Publications
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Distribution Cutoff for Clusters near the Gel Point.
ACS polymers Au
2022; 2 (5): 361-370
Abstract
The mechanical and dynamic properties of developing networks near the gel point are susceptible to the distribution of clusters coexisting with percolating networks. The distribution of cluster numbers follows a broad power law, wrapped by a cutoff function that rapidly decays at a characteristic size. The form of the cutoff function has been speculated based on known results from lattice percolation and, in certain cases, solved. We obtained this cutoff function from simulated dynamic clusters of polymeric precursor chains using a hybrid Monte Carlo algorithm. The results obtained from three different precursor chain lengths are consistent with each other and are consistent with the expectation from lattice percolation.
View details for DOI 10.1021/acspolymersau.2c00020
View details for PubMedID 36254314
View details for PubMedCentralID PMC9562459
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Suspension electrolyte with modified Li+ solvation environment for lithium metal batteries.
Nature materials
1800
Abstract
Designing a stable solid-electrolyte interphase on a Li anode is imperative to developing reliable Li metal batteries. Herein, we report a suspension electrolyte design that modifies the Li+ solvation environment in liquid electrolytes and creates inorganic-rich solid-electrolyte interphases on Li. Li2O nanoparticles suspended in liquid electrolytes were investigated as a proof of concept. Through theoretical and empirical analyses of Li2O suspension electrolytes, the roles played by Li2O in the liquid electrolyte and solid-electrolyte interphases of the Li anode are elucidated. Also, the suspension electrolyte design is applied in conventional and state-of-the-art high-performance electrolytes to demonstrate its applicability. Based on electrochemical analyses, improved Coulombic efficiency (up to ~99.7%), reduced Li nucleation overpotential, stabilized Li interphases and prolonged cycle life of anode-free cells (~70 cycles at 80% of initial capacity) were achieved with the suspension electrolytes. We expect this design principle and our findings to be expanded into developing electrolytes and solid-electrolyte interphases for Li metal batteries.
View details for DOI 10.1038/s41563-021-01172-3
View details for PubMedID 35039645
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Rational solvent molecule tuning for high-performance lithium metal battery electrolytes
NATURE ENERGY
2022
View details for DOI 10.1038/s41560-021-00962-y
View details for Web of Science ID 000742253900001
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Distribution cutoff for clusters near the gel point
ACS Polymers Au
2022
View details for DOI 10.1021/acspolymersau.2c00020
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Steric Effect Tuned Ion Solvation Enabling Stable Cycling of High-Voltage Lithium Metal Battery.
Journal of the American Chemical Society
2021
Abstract
1,2-Dimethoxyethane (DME) is a common electrolyte solvent for lithium metal batteries. Various DME-based electrolyte designs have improved long-term cyclability of high-voltage full cells. However, insufficient Coulombic efficiency at the Li anode and poor high-voltage stability remain a challenge for DME electrolytes. Here, we report a molecular design principle that utilizes a steric hindrance effect to tune the solvation structures of Li+ ions. We hypothesized that by substituting the methoxy groups on DME with larger-sized ethoxy groups, the resulting 1,2-diethoxyethane (DEE) should have a weaker solvation ability and consequently more anion-rich inner solvation shells, both of which enhance interfacial stability at the cathode and anode. Experimental and computational evidence indicates such steric-effect-based design leads to an appreciable improvement in electrochemical stability of lithium bis(fluorosulfonyl)imide (LiFSI)/DEE electrolytes. Under stringent full-cell conditions of 4.8 mAh cm-2 NMC811, 50 mum thin Li, and high cutoff voltage at 4.4 V, 4 M LiFSI/DEE enabled 182 cycles until 80% capacity retention while 4 M LiFSI/DME only achieved 94 cycles. This work points out a promising path toward the molecular design of non-fluorinated ether-based electrolyte solvents for practical high-voltage Li metal batteries.
View details for DOI 10.1021/jacs.1c09006
View details for PubMedID 34709034
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Dendrite Suppression by a Polymer Coating: A Coarse-Grained Molecular Study
ADVANCED FUNCTIONAL MATERIALS
2020
View details for DOI 10.1002/adfm.201910138
View details for Web of Science ID 000513653700001
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Transient Voltammetry with Ultramicroelectrodes Reveals the Electron Transfer Kinetics of Lithium Metal Anodes
Adv. Energy Lett.
2020; 5: 701-709
View details for DOI 10.1021/acsenergylett.0c00031
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Impact of Liquid-Crystalline Chain Alignment on Charge Transport in Conducting Polymers
MACROMOLECULES
2019; 52 (22): 8932–39
View details for DOI 10.1021/acs.macromol.9b01729
View details for Web of Science ID 000500039300040