V. Focused Fundamental Research - EERE - U.S. Department of ...

More documents

Recommendations

Info

Smith, Borodin – U. Utah V.D.3 Molecular Dynamics Simulation Studies of Electrolytes and Interfaces (U. Utah) properties, good mechanical properties and electrochemical stability is of paramount importance. Particularly challenging is development of electrolytes and/or additives that allow use of high voltage cathode materials. Approach Our approach to simulation of bulk electrolytes, SEI layers, and electrode/electrolyte interfaces is multifold. First, we carry out high-level quantum-chemistry (DFT and correlated methods) to study the structure of electrode materials, their surfaces, interactions between electrodes and electrolytes (including reactions), and the interaction between electrolyte components. Second, where possible and appropriate, we utilize quantumchemistry based force fields and non-reactive simulation methods. These studies include bulk electrolytes, model SEI layers and electrode/electrolyte interfaces. Third, we utilize an electroactive interface model to study electrolyte structure and charge transfer processes at electrode/electrolyte interfaces where control of electrode potential is paramount. Finally, we utilized atomistic MD simulations with ReaxFF, a reactive force field developed by Adri van Duin at Penn State and William Goddard at Caltech. This simulation method combines accuracy in modeling reaction energies and barriers with the capability to simulate systems large enough and over sufficiently long time to capture the diffusive properties of molecules necessary to adequately capture important chemical and structural reorganization during SEI formation. The ReaxFF is an empirical potential that is parameterized to reproduce results from quantum chemistry calculations. Results Quantum chemistry studies of the influence of anion (PF 6 - ) on the solvent oxidative stability and oxidative decomposition pathways were performed in collaboration with the Army Research Laboratory. Oxidative stability of PC/PF 6 - complex was found to be reduced compared to the intrinsic oxidative stability of PC solvent due to the formation of HF upon oxidation of PC/PF 6 - . Importantly, the presence of the PF 6 - anion also altered the PC oxidative decomposition pathways. In collaboration with van Duin (Penn State), the reactive molecular dynamics simulation methods utilizing ReaxFF has been extended to accurately treat both oxidation and reduction at electrode interfaces. This effort required modification of the ReaxFF code to allow for control of electrode charge. The new ReaxFF code (q- ReaxFF) will handle inert (carbon, metal) electrodes and active (graphite, LiNi 0.5 Mn 1.5 O 4 ) electrode materials. For the purpose of parameterizing both reactive (ReaxFF) and non-reactive (Lucretius) molecular dynamics simulation models for metal and LiNi 0.5 Mn 1.5 O 4 electrodes we have carried out DFT studies of bulk crystal and surfaces utilizing the Vienna ab-initio simulation package (VASP). These calculations have allowed us to determine interactions between metal substrates and electrode materials and will allow us to parameterize partial charges, polarizabilities, dispersion/repulsion interactions and reactivity with LiNi 0.5 Mn 1.5 O 4 . We have calculated basic properties (including energies, internal stresses, and unit cell geometries) for components of the LiNi 0.5 Mn 1.5 O 4 high voltage spinel as well as for the spinel directly in order to aid parameterization of the forcefield (ReaxFF) for reactive molecular dynamics simulations of the high voltage spinel. We have also investigated β-MnO 2 (pyrolusite) under a number of compression conditions ranging between 50 and 120 percent of the original volume. For investigations of the LiNi 0.5 Mn 1.5 O 4 spinel, we have begun by reproducing published results for the bulk spinel, including the predicted average voltage of the cell of approximately 4.7 V. The relaxed geometries and energies which will serve, in conjunction with the MnO 2 data, for parameterization of ReaxFF for the spinel. We have also utilized DFT to identify the lowest energy surfaces of LiNi 0.5 Mn 1.5 O 4. Our reactive MD simulations have demonstrated that various alkyl carbonates are formed in the outer SEI layer at the anode due to single electron reduction. To improve our understanding of Li + transport through the electrolyte/SEI interface and through the SEI itself extensive simulations of model SEIs comprised of dilithium alkylcarbonates (ethylene and butylene) have been initiated using a new polarizable force field. The force field has been re-parameterized against higher-level quantum chemistry calculations and fit to accurately reproduce conformational properties of alkylcarbonates, electrostatic field around these molecules in vacuum, and molecular dipole moments. Conclusions and Future Directions We hope to continue investigating low energy surfaces of LiNi 0.5 Mn 1.5 O 4 by including oxygen in a nonstoichiometric ratio as necessary to cap unterminated transition metal bonds, or direct calculation of the reaction of elemental oxygen with the ideal surfaces to determine whether or not oxygen termination of the exposed surface plays an important role. These studies will be extended to include reactions with electrolyte components, including candidates for high-voltage electrolytes and additives for formation of stable cathode SEI layers. Oxidative decomposition pathways for these materials will also be determined. ReaxFF simulations of oxidation/reduction of electrolytes as a function of electrode potential will also be carried out, allowing us to see initial reactions and ultimately formation of SEI layers. FY 2011 Annual Progress Report 603 Energy Storage R&D
V.D.3 Molecular Dynamics Simulation Studies of Electrolytes and Interfaces (U. Utah) Smith, Borodin – U. Utah FY 2011 Publications/Presentations 1. 2011 DOE Annual Peer Review Meeting Presentation. 2. O. Borodin, J. Vatamanu, G. Smith “Molecular Insight into Ionic Liquid Behavior in Double Layer Capacitors and in Electrolytes for Lithium Batteries” 4th Congress on Ionic Liquids (COIL-4), June 15-18, 2011, Crystal City Hilton, Arlington, Virginia (http://coil-4.org/invited-speakers/) 3. O. Borodin, “Modeling of Liquid and Ionic Liquid Electrolytes for Energy Storage Applications” 10X Advanced Battery R&D, Future Storage Platforms, January 10-12, 2010 at Techmart in Santa Clara, CA 4. Lidan Xing, Jenel Vatamanu, Oleg Borodin, Grant D Smith “Understanding Electrolyte Stability from DFT Calculations and Double Layer Structure from MD Simulations” 4th Symposium on Energy Storage: Beyond Lithium Ion, Pacific Northwest National Laboratory, June 7-9, 2011 (poster) 5. Dmitry Bedrov, Grant D. Smith and Adri van Duin, "Molecular dynamics simulations using ReaxFF: Mechanisms of outer SEI formation via single electron reduction of ethylene carbonate (EC)", American Chemical Society, Denver, CO, August 27- September 1, 2011. 6. Grant D. Smith and Oleg Borodin, “Ionic Liquid Electrolytes for Lithium Ion Batteries: Insights from Molecular Dynamics Simulations”, American Chemical Society, Denver, CO, August 27- September 1, 2011. 7. Grant D. Smith and Oleg Borodin, “Ionic Liquid Electrolytes for Lithium Ion Batteries: Insights from Molecular Dynamics Simulations”, General Motors Central Research, Warren, MI, August 10, 2011. 8. Grant D. Smith and Oleg Borodin, “Polymer Electrolytes for Lithium Ion Batteries: Insights from Molecuar Dynamics Simulations”, American Chemical Society, Anaheim, CA, March 27 – 31, 2011. 9. Dangxin Wu, Grant D. Smith and Dmitry Bedrov, “Simulations of Lithium Ion Batteries: Electrolytes, Electrodes and Interfaces”, NAATBatt, Louisville, KY, September 7-8, 2011. 10. Grant D. Smith and Oleg Borodin, “Polymer Electrolytes for Lithium Ion Batteries: Insights from Molecuar Dynamics Simulations”, IBM Almaden Research Center, San Jose, CA, October 10, 2011. 11. Grant D. Smith, Dmitry Bedrov and Adri van Duin, "Molecular dynamics simulations using ReaxFF: Mechanisms of outer SEI formation via single electron reduction of ethylene carbonate (EC)", Electrochemical Society, Boston, MA, October 9-14, 2011. 12. Lidan Xing, Jenel Vatamanu, Oleg Borodin, Grant D Smith “Understanding Electrolyte Stability from DFT Calculations and Double Layer Structure from MD Simulations”, Electrochemical Society, Boston, MA, October 9-14, 2011. 13. Xing, L.; Borodin, O.; Smith, G. D.; Li, W. "A Density Function Theory Study of the Role of Anions on the Oxidative Decomposition Reaction of Propylene Carbonate" J. Phys. Chem. A (published on the web) 14. Vatamanu, J.; Cao, L.; Borodin, O.; Bedrov, D.; Smith, G. D."On the Influence of Surface Topography on the Electric Double Layer Structure and Differential Capacitance of Graphite/ionic Liquid Interfaces" J. Phys. Chem. Lett. 2011, 2, 2267-2272. 15. Vatamanu, J.; Borodin, O.; Smith, G.D. “Molecular Dynamics Simulation Studies of the Structure of a Mixed Carbonate/LiPF 6 Electrolyte as a Function of Electrode Potential”, J. Phys. Chem. C, submitted 16. Bedrov, D.; Smith, G.D.; van Duin, A.C.T.; Reactions of Singly-Reduced Ethylene Carbonate in Lithium Battery Electrolytes. A Molecular Dynamics Simulation Study”, J. Phys. Chem. A, submitted Energy Storage R &D 604 FY 2011 Annual Progress Report
Page 1 and 2:
V. FOCUSED FUNDAMENTAL RESEARCH Int
Page 3 and 4:
V.A Introduction Duong - DOE, Srini
Page 5 and 6:
V.B Cathode Development V.B.1 First
Page 7 and 8:
V.B.1 First Principles Calculations
Page 9 and 10:
V.B.1 First Principles Calculations
Page 11 and 12:
V.B.2 Cell Analysis, High-energy De
Page 13 and 14:
V.B.3 Olivines and Substituted Laye
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
V.B.4 Stabilized Spinels and Nano O
Page 21 and 22:
V.B.4 Stabilized Spinels and Nano O
Page 23 and 24:
V.B.5 The Synthesis and Characteriz
Page 25 and 26:
V.B.5 Synthesis & Characterization
Page 27 and 28:
V.B.6 Cell Analysis-Interfacial Pro
Page 29 and 30:
V.B.6 Cell Analysis-Interfacial Pro
Page 31 and 32:
V.B.7 Role of Surface Chemistry on
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
V.B.8 Characterization of New Catho
Page 41 and 42:
V.B.8 Characterization of New Catho
Page 43 and 44:
V.B.9 Layered Cathode Materials (AN
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
V.B.10 Development of High Energy C
Page 51 and 52:
V.B.10 Development of High Energy C
Page 53 and 54:
V.B.11 Crystal Studies on High-ener
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
V.B.12 Developing Materials for Lit
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
V.B.13 Studies on the Local SOC and
Page 67 and 68:
V.B.13 Studies on the Local SOC and
Page 69 and 70:
V.B.14 New Cathode Projects (LBNL)
Page 71 and 72:
V.C.1 Nanoscale Composite Hetero-st
Page 73 and 74:
V.C.1 Nanoscale Composite Hetero-st
Page 75 and 76:
V.C.2 Interfacial Processes - Diagn
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
V.C.3 Search for New Anode Material
Page 83 and 84:
V.C.4 Nano-structured Materials as
Page 85 and 86:
V.C.4 Nano-structured Materials as
Page 87 and 88: V.C.5 Development of High Capacity
Page 89 and 90: V.C.5 Development of High Capacity
Page 91 and 92: V.C.6 Advanced Binder for Electrode
Page 93 and 94: V.C.6 Advanced Binder for Electrode
Page 95 and 96: V.C.7 Three-Dimensional Anode Archi
Page 97 and 98: ARGONNE2_CDJ403T me Pro ile V.C.7 T
Page 99 and 100: V.C.8 Metal-Based High-Capacity Li-
Page 101 and 102: V.C.8 Metal-Based High-Capacity Li-
Page 103 and 104: V.C.9 New Layered Nanolaminates for
Page 105 and 106: V.C.9 New Layered Nanolaminates for
Page 107 and 108: V.C.10 Atomic Layer Deposition for
Page 109 and 110: V.C.10 Atomic Layer Deposition for
Page 111 and 112: V.C.11 Synthesis and Characterizati
Page 113 and 114: V.C.11 Polymer-Coated Layered SiOx-
Page 115 and 116: V.C.12 Synthesis and Characterizati
Page 117 and 118: V.C.12 Silicon Clathrates for Anode
Page 119 and 120: V.C.12 Silicon Clathrates for Anode
Page 121 and 122: V.C.13 Wiring Up Silicon Nanopartic
Page 123 and 124: V.C.13 Wiring Up Silicon Nanopartic
Page 125 and 126: V.C.14 Hard Carbon Materials for Hi
Page 127 and 128: V.C.14 Hard Carbon Materials for Hi
Page 129 and 130: V.D.1 Polymer Electrolytes for Adva
Page 131 and 132: V.D.1 Polymer Electrolytes for Adva
Page 133 and 134: V.D.2 Interfacial Behavior of Elect
Page 135 and 136: V.D.2 Interfacial Behavior of Elect
Page 137: V.D.3 Molecular Dynamics Simulation
Page 141 and 142: V.D.4 Bi-functional Electrolytes fo
Page 143 and 144: V.D.4 Bi-functional Electrolytes fo
Page 145 and 146: V.D.5 Advanced Electrolyte and Elec
Page 147 and 148: V.D.6 Inexpensive, Nonfluorinated (
Page 149 and 150: V.D.6 Nonfluorinated (or Partially
Page 151 and 152: V.D.7 Development of Electrolytes f
Page 157 and 158: V.D.8 Sulfones with Additives as El
Page 159 and 160: V.D.8 Sulfones with Additives as El
Page 161 and 162: V.D.9 Long-lived Polymer Electrolyt
Page 163 and 164: V.E Cell Analysis, Modeling, and Fa
Page 165 and 166: V.E.1 Electrode Fabrication and Fai
Page 167 and 168: V.E.2 Modeling-Thermo-electrochemis
Page 169 and 170: V.E.2 Thermo-electrochemistry, Capa
Page 171 and 172: V.E.3 Intercalation Kinetics and Io
Page 177 and 178: V.E.4 Mathematical Modeling of Next
Page 179 and 180: V.E.5 Analysis and Simulation of El
Page 181 and 182: V.E.5 Analysis and Simulation of El
Page 183 and 184: V.E.6 Investigation of Critical Par
Page 185 and 186: V.E.6 Investigation of Critical Par
Page 187 and 188: V.E.7 Predicting/Understanding New
Page 189 and 190:
V.E.8 New Electrode Designs for Ult
Page 191 and 192:
V.E.8 New Electrode Designs for Ult
Page 193 and 194:
V.E.9 In Situ Electron Spectroscopy
Page 195 and 196:
V.E.9 In situ Electron Spectroscopy
Page 197 and 198:
V.F.1 Energy Frontier Research Cent
Page 199 and 200:
V.F.1 Energy Frontier Research Cent
Page 201 and 202:
V.F.2 Novel In Situ Diagnostics Too
Page 203 and 204:
V.F.2 Novel In Situ Diagnostics Too
Page 205 and 206:
V.G Integrated Lab-Industry Researc
Page 207 and 208:
Page 209 and 210:
show all

V. Focused Fundamental Research - EERE - U.S. Department of ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?