Advanced Materials for Energy Conversion and Storage VII: Energy Storage with Emphasis on Batteries II
Sponsored by: TMS Functional Materials Division, TMS: Energy Conversion and Storage Committee
Program Organizers: Jung Choi, Pacific Northwest National Laboratory; Soumendra Basu, Boston University; Amit Pandey, Lockheed Martin Space; Paul Ohodnicki, University Of Pittsburgh; Kyle Brinkman, Clemson University; Partha Mukherjee, Purdue University; Surojit Gupta, University of North Dakota
Thursday 8:30 AM
March 18, 2021
Room: RM 23
Location: TMS2021 Virtual
Session Chair: Eric Detsi, University of Pennsylvania; Scott Roberts, Sandia National Laboratory
8:30 AM
Mesoscale Mechanics: Simulating the Role of Stress on Electrode Electrochemical Performance: Scott Roberts1; Mark Ferraro1; Jeffrey Horner1; Julia Meyer2; Benjamin Ng1; 1Sandia National Laboratories; 2Purdue University
Mesoscale simulations are increasingly popular for assessing the electrochemical performance of battery electrodes. While many of the simulations consider effective transport properties or solve species/electrical transport and electrochemical reactions, most do not consider the impact that mechanical stress has on electrochemical performance, safety, and aging. In this talk, we present mesoscale simulations that couple electrochemical performance with mechanical deformation and stress for a variety of battery electrodes. First, we focus on the interaction between diffusion-induced stresses in particles and the conductive binder domain (CBD) in NMC electrodes, characterizing the impact of calendaring, electrode recipe, and CBD morphology. We next discuss FeS2, which undergoes both intercalation and conversion reactions. Finally, we address lithium metal anodes, whose electrochemical performance is strongly tied to the stress state at its interface, while stresses can mechanically modify the pore structure of the neighboring separator, further changing transport processes.
9:00 AM
Metal-sulfur Nanocomposite for Developing High-loading Electrochemical Cathode: Sheng-Heng Chung1; Cun-Sheng Cheng1; 1National Cheng Kung University
High-performance sulfur cathodes with a high amount of active material and stable electrochemical properties at a lean electrolyte hold the key to realize high-energy-density lithium-sulfur batteries as the promising beyond-lithium-ion technology. However, the development of practically-available sulfur cathodes has not yet obtained a significant breakthrough. We present here a metal-sulfur nanocomposite possessing a conductive metal shell coated on sulfur particles to improve the cathode conductivity and polysulfide retention. The metal-sulfur nanocomposite cathode exhibits high electrochemical utilization and kinetics with high charge-storage capacity of 1,008 mA∙h g-1 and excellent rate performance from C/20 to C/2 rates with stable cyclability for 200 cycles. These improved cathode performances are realized by the high-loading cathode with a high sulfur loading of 14 mg cm-2 and a high sulfur content of 74 wt% in a lean electrolyte condition with an electrolyte-to-sulfur ratio of 7 µL mg-1.
9:20 AM
Molecular-level Characterization of the Electrode-electrolyte Interfaces in Li Batteries: Lauren Marbella1; 1Columbia University
Most next generation Li battery materials suffer from severe interfacial instabilities. Here, we leverage our unique abilities in solid-state NMR and MRI to characterize, at the molecular-level, the composition, arrangement, and dynamics of the solid electrolyte interphases that form on the surface of emerging anode and cathode technologies for Li batteries. We find that interphase stability (e.g. solubility) and composition (e.g. high conductivity compounds) are paramount to controlling high Coulombic efficiencies and achieving high capacity retentions for a range of electrolyte formulations and cell configurations. Insight from this work provides some of the first atomistic descriptors of electrode-electrolyte interfacial reactions that enable safe and efficient battery operation.
9:50 AM Invited
New Insights Linking Material Properties and Performance of the Lithium SEI: Betar Gallant1; 1MIT
Achieving a stable and reversible Li metal anode would enable a step-change in Li-ion battery energy densities if critical issues of reactivity, insufficient Coulombic Efficiency, electrolyte consumption and loss of active Li can be addressed. The chemistry and physics governing the solid electrolyte interphase (SEI), which underlies these issues, require further illumination so that better interfaces can be designed. I will describe our studies on individual ionic SEI phases as model interfaces, which have revealed new quantitative insights into transport properties at the chemical potential of Li. Next, I describe X-ray absorption spectroscopy measurements used to probe the chemical stability of these phases in common electrolytes, revealing chemical insights into SEI evolution. Finally, I present emerging understanding of dynamic processes at the Li interface during cycling, and new chemical insights correlating with increasing Coulombic Efficiency. Integration of this knowledge to guide design of improved SEI chemistries will be discussed.
10:20 AM
Simulations of Phase Transformation in Complex Graphite Electrode Microstructures: Affan Malik1; Kent Snyder2; Minghong Liu2; Hui-Chia Yu1; 1Michigan State University; 2Ford Auto Company
Phase transformations occur in several electrode materials (e.g., graphite anode and LiCoO2 cathode) of Li-ion batteries during (de)intercalation. The process of (de)lithiation phase transformation determines the cell performance during operations. In this work, we present a framework for simulating phase transformations and investigating the dynamics in complex porous electrode microstructures. The Cahn-Hilliard equation is employed to model the phase transformations induced by Li insertion/extraction. The Smoothed Boundary Method is utilized to circumvent the challenge of generating conformal meshes on the complex porous microstructures for simulations. Experimentally measured material properties and reconstructed 3D graphite anodes are used in the simulations, establishing a bridge between experiments and simulations. Anisotropic Li diffusion in the graphite particles is considered in the simulations as well. The simulations reveal the phase transformation dynamics in the complex porous electrodes at different cycling rates and how they affect the cell’s performance.