Advanced Materials for Energy Conversion and Storage: Energy Storage I
Sponsored by: TMS Functional Materials Division, TMS: Energy Conversion and Storage Committee
Program Organizers: Amit Pandey, LG Fuel Cell Systems Inc.

Tuesday 2:00 PM
February 28, 2017
Room: 15A
Location: San Diego Convention Ctr

Session Chair: Partha Mukherjee, TAMU; Leela Arava , Wayne

2:00 PM  Keynote
Direct Electrodeposition of High Performance Solid and Mesostructured Li-ion Cathodes and Anodes: Paul Braun1; Hailong Ning2; Huigang Zhang3; 1University of Illinois at Urbana-Champaign; 2Xerion Advanced Battery Company; 3Nanjing University
    New synthetic routes often provide opportunities for innovation. Recently we have made considerable advances in the direct electrodeposition at modest temperatures of high performance tin-based Li-ion anodes and LiCoO2, LiMn2O4, and Al-doped LiCoO2-based Li-ion cathodes. The electrolytically active materials were formed either as solid films, or where significant volume changes upon cycling are present, off of a 3D mesostructured template. The capacities are near-theoretical, and in the case of the electroplated oxides, the crystallinities and electrochemical capacities of the oxides are comparable to powders synthesized at much higher temperatures (700 ~ 1000C). The electrodeposition method significantly broadens the scope of battery form factors and functionalities, enabling a variety of highly desirable battery properties including microbatteries, and high energy, high power, and flexible designs.

2:30 PM  Invited
A Multi-Scale Approach to Li-Ion Battery Analysis Using 2D, 3D, and 4D Microscopy: Jeff Gelb1; Stefanie Freitag2; Will Harris1; Arno Merkle1; 1Carl Zeiss X-ray Microscopy; 2Carl Zeiss Microscopy
    Here, we present a comprehensive imaging protocol for commercial Li-ion batteries and discuss the relevant understanding that is achieved at each length scale. The study begins using 2D light microscopy for fast overview imaging, followed by non-destructive 3D imaging with X-Ray and focused ion beam microscopy (XRM and FIB-SEM, respectively) to capture the fine details of the transport pathways. Complementary spectroscopic analysis with EDS and Raman microscopy further clarifies the 2D and 3D results, by providing chemical information to identify the structures. Finally, time-evolution (4D) imaging studies with non-destructive XRM elucidate the change that occur within the battery microstructures as a function of aging. Applying the techniques outlined above creates a unified spatial and chemical representation of the structure that can be used for subsequent modeling and simulation studies. The results of some example studies will additionally be presented, in order to illustrate the true power of image-based characterization.

2:55 PM  
First Principles Simulations of Lithium Ion Transport through Graphite/Electrolyte Interfaces: Vincenzo Lordi1; Mitchell Ong1; Tuan Pham1; Kyoung Kweon1; John Pask1; 1Lawrence Livermore National Lab
    The interface between anode and electrolyte plays a key role in the performance of lithium ion batteries. Here, we use first principles molecular dynamics to examine the solvation and energetics of Li transport across a typical anode interface comprising graphite and carbonate electrolyte. We find the coordination number of Li+ decreases as it approaches the graphite surface, suggesting that Li+ sheds its solvation shell to enter the anode. We determined the free energy profile for Li insertion or extraction from graphite, considering different surface orientations and chemical terminations. The energy required for intercalation depends on the graphite chemical termination and is affected strongly by electrostatic interactions between Li+ and the terminating species. We discuss the implications of these effects on Li transport dynamics related to the anode surface chemistry and Li+ solvation structure in the electrolyte, as well as the effects of applied voltage. Prepared by LLNL under Contract DE-AC52-07NA27344.

3:15 PM  Invited
Operando Structural and Chemical Characterization during Li-ion Battery Cycling: Shen Dillon1; Ching-Yen Tang1; 1University of Illinois at Urbana-Champaign
    This talk focuses on understanding the evolution of Li-ion electrodes during cycling with emphasis on structural changes induced as strain accommodation mechanisms and changes in chemical bonding. Characterizing these effects under operando conditions is critical due to both the environmental sensitivity of the electrode material and the spatial heterogeneity of the reactions. We have developed a flexible in-situ platform that can be applied for electrochemical cycling in TEM, SEM, XPS, AES, and AFM. The talk will highlight work on strain accommodation during alloying reactions, whisker formation during Li deposition, and changes in chemical bonding during conversion reactions.

3:40 PM Break

4:00 PM  
Nanoscale Characterization of Li-ion Battery Cathodes Using Atom Probe Tomography and Correlative Microscopy: Arun Devaraj1; Ethan Vo1; Pengfei Yan1; Chongmin Wang1; Vijaya Murugesan1; 1Pacific Northwest National Laboratory
    Understanding the influence of synthesis methods and the electrochemical cycling on the electrode materials is critical for improving the performance of current energy storage materials. Light elements like Li, Na and O, which are critical for energy storage materials are extremely difficult to characterize quantitatively by conventional electron microscopy techniques. Authors have recently demonstrated the benefit of using atom probe tomography (APT) in conjunction with TEM for understanding Li and other element distribution in as-fabricated and cycled cathodes [1]. In this talk we will present new insights gained by such an approach for advanced Li-ion battery cathodes LiNi0.5Mn1.5O4, Li1.2Ni0.2Mn0.6O2 and Li1.2Mn0.55Ni0.15Co0.10O2. Also an integrated multi-modal imaging of Li-ion battery cathodes, using TEM for structure, APT for composition and scanning transmission xray-microscopy (STXM) for chemical state, all at nanoscale resolution providing a comprehensive understanding of the electrode materials will be presented. [1] A. Devaraj et al, Nature Communications, 6, 2015

4:20 PM  Invited
Atomistic Simulations of Ionic Liquid and Polymer Electrolytes: From Bulk Phases to Interfacial Behavior: John Lawson1; Justin Haskins1; 1NASA Ames Research Center
    Ionic liquids and polymers are candidate electrolytes for high-energy density, rechargeable batteries. We present an extensive computational analysis with experimental comparisons of bulk and interfacial properties of three ionic liquid electrolytes ([pyr14][TFSI], [pyr13][FSI], and [EMIM][BF4]) as a function of Li-salt doping. We investigated the bulk electrolyte using quantum chemistry and ab initio molecular dynamics to elucidate the solvation structure of Li+. MD simulations using polarizable force fields were performed, from which we obtained an array of thermodynamic and transport properties. We computed the electrochemical window of the electrolytes across a range of Li+-doping levels, including the effect of the liquid environment. In addition, we considered these Li-doped electrolytes at ideal electrified interfaces to evaluate the differential capacitance and the equilibrium Li+ distribution in the double layer. Finally, we investigated polymers as candidate structural electrolytes. We report results for ionic conductivity, glass transition temperature and bulk modulus for representative polymer systems.

4:45 PM  Invited
Chemomechanics in Li-ion batteries: Kejie Zhao1; 1Purdue University
    Mechanical issues are universal in all forms of energy conversion, storage, and harvesting. A Li-ion battery is a system that dynamically couples electrochemistry and mechanics. The electrochemical processes of Li insertion and extraction lead to rich phenomena of mechanics, such as large deformation, plasticity, fracture, and fatigue. Likewise, mechanics influences interfacial reactions, ionic transport, stability of chemical reactions, and phase transformations in the electrodes. In this talk, I will highlight the intimate coupling between mechanics and electrochemistry in Li-ion batteries. Theories of diffusion-induced stresses, coupled Li diffusion and large elasto-plastic deformation, concurrent chemical reactions and flow, and fracture of electrodes will be presented. First-principles simulations and in-situ experiments that emphasize the mechanisms of reactions and deformation will also be discussed.