Bulletin of the American Physical Society
APS March Meeting 2016
Volume 61, Number 2
Monday–Friday, March 14–18, 2016; Baltimore, Maryland
Session R54: Materials for Energy Storage Devices IIFocus
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Sponsoring Units: GERA FIAP Room: Hilton Inner Harbor Holiday Ballroom 5 |
Thursday, March 17, 2016 8:00AM - 8:36AM |
R54.00001: Azobenzene-based Polymers for Solar Thermal Batteries . Invited Speaker: Dhandapani Venkataraman Azobenzene exists as two isomers, a higher energy cis-isomer and a lower energy trans-isomer. The isomers interconvert under light or heat. Recently, there is a renewed interest in capturing the difference in the energies of the isomers and using azobenzene-based molecules as active layers for solar thermal batteries. My research group has been exploring azobenzene-based polymers as candidates for solar thermal batteries. In this talk, I will show that the azo-benzene moieties can be converted to the cis-form using light and converted back to the trans form using mechanical force. I will provide some of our recent results that indicate that high energy densities can be achieved in these polymers. [Preview Abstract] |
Thursday, March 17, 2016 8:36AM - 8:48AM |
R54.00002: Lithiation of Ag$_x$MnO$_2$: Insights from first principles Merzuk Kaltak, Marivi Fernandez-Serra, Mark Hybertsen Stable electrode materials being able to capture high lithium concentrations are attracting considerable interest in science as well as industry. Recently hollandite $\alpha$-MnO$_2$ based structures are moving into the focus of electrochemists and are considered to be promising electrodes for increasing the capacity and efficiency of rechargeable lithium batteries. These favorable properties are mainly due to the tunnel structure consisting out of stacked 1$\times$1 and 2$\times$2 MnO$_2$ octahedra in the z-axis. It has been shown that large ions such as silver or potassium can stabilize and increase the cyclicity of pure hollandite $\alpha$-MnO$_2$ considerably. In this work we present new insights from first principles for lithiated silver hollandite Li$_y$Ag$_x$MnO$_2$ and demonstrate that the formation of oxygen vacancies play an important role for lithium diffusion. [Preview Abstract] |
Thursday, March 17, 2016 8:48AM - 9:00AM |
R54.00003: First Principles Investigation of the Geometrical and Electrochemical Properties of Na$_4$P$_2$S$_6$ and Li$_4$P$_2$S$_6$. Larry E. Rush Jr., N.A.W. Holzwarth First principles simulations are used to examine the structural and physical properties of Na$_4$P$_2$S$_6$ in comparison with its Li$_4$P$_2$S$_6$ analog. Four model structures are considered including the $C2/m$ structure recently reported by Kuhn and co-workers\footnote{ZAAC {\bf{640}}(5):689-692 (2014)} from their analysis of single crystals of Na$_4$P$_2$S$_6$, and three structures related to the $P6_3/mcm$ structure with P site disorder found in 1982 by Mercier and co-workers\footnote{JSSC {\bf{43}}:151-162 (1982)} from their analysis of single crystals of Li$_4$P$_2$S$_6$. The computational results indicate that both Na$_4$P$_2$S$_6$ and Li$_4$P$_2$S$_6$ have the same disordered ground state structures consistent with the $P6_3/mcm$ space group, while the optimized $C2/m$ structures have higher energies by 0.1~eV and 0.4~eV per formula unit for Na$_4$P$_2$S$_6$ and Li$_4$P$_2$S$_6$, respectively. %Activation energies for Na-ion %vacancy migration were computed to be % smaller than the Li analogs in %all of the structural models. Simulations of ion migration suggest that Na$_4$P$_2$S$_6$ may have more favorable ionic conductivity compared to Li$_4$P$_2$S$_6$. [Preview Abstract] |
Thursday, March 17, 2016 9:00AM - 9:12AM |
R54.00004: Quinone Derivatives for Lithium-Ion Batteries: First-Principles Density Functional Theory Modeling Seung Soon Jang, Ki Chul Kim, Tianyuan Liu, Seung Woo Lee The Li binding thermodynamics and redox potentials of seven different quinone derivatives are investigated as positive electrode candidates for lithium-ion batteries. First, using the density functional theory (DFT) calculations on the interactions between the quinone derivatives and Li ions, it is found that Li ions are dominantly bound with carbonyl groups of the molecules. Second, it is revealed that the redox chemistry of the quinone derivatives can be tuned by the modification of their chemical structures. Further DFT-based investigations on the redox potentials of the Li-bound quinone derivatives provide an insight on the change in their redox chemistry during the discharging processes. The redox potential and charge capacity are improved by modifying the quinone derivatives with electron-withdrawing carboxylic groups. Through this study, it is also found that the cathodic activity of a quinone derivative during the discharging processes strongly relies on the solvation free energy effect as well as the number of available carbonyl groups for further Li binding. To the best of our knowledge, the changes in the redox potential of the redox-active molecules during the discharging processes is reported for the first time. [Preview Abstract] |
Thursday, March 17, 2016 9:12AM - 9:24AM |
R54.00005: Lithiation of $Li_{2}SnO_{3}$ and $Li_{2}SnS_{3}$ in context of Li-ion battery materials Jason Howard, N. A. W. Holzwarth The closed pack layered crystal material (space group 15 ($C2/c$)) $Li_{2}SnO_{3}$ has been studied as a possible anode material since the late 1990’s.\footnote{Courtney \& Dahn, JES {\bf{144}}, 2045(1997)}$^,$\footnote{Zhang et al., J. Alloy compd. {\bf{415}}, 229(2006)}$^,$\footnote{Wang et al., Surf. Interface Anal. {\bf{45}}, 1297(2013)} The material undergoes an irreversible decomposition to $Li_{2}O$ and $Li_{X}Sn$ alloys during the first lithiation cycle. The crystal material $Li_{2}SnS_{3}$ of the same structure was recently proposed as an electrolyte material.\footnote{Brant et al., Chem.Mater. {\bf{27}},189 (2015)} The question is posed whether $Li_{2}SnS_{3}$ would be a good electrolyte or whether it could function as an anode material similar to $Li_{2}SnO_{3}$. In this research a model is proposed for the lithiation process of $Li_{2}SnO_{3}$ and $Li_{2}SnS_{3}$; $Li$ -- $Li_{2}SnS_{3}$ interfaces are also examined. The results show $Li_{2}SnO_{3}$ begins to decompose at approximately $Li_{2 + 0.5}SnO_{3}$. In $Li_{2}SnS_{3}$ the lithiation process shows it can lithiate to $Li_{2+1}SnS_{3}$ without significant lattice distortion, volume expansion, or decomposition. $Li$ -- $Li_{2}SnS_{3}$ interfaces are shown to be unstable, showing the formation of $Li_{2}S. [Preview Abstract] |
Thursday, March 17, 2016 9:24AM - 9:36AM |
R54.00006: Accelerated materials design of fast oxygen ionic conductors based on first principles calculations Xingfeng He, Yifei Mo Over the past decades, significant research efforts have been dedicated to seeking fast oxygen ion conductor materials, which have important technological applications in electrochemical devices such as solid oxide fuel cells, oxygen separation membranes, and sensors. Recently, Na$_{0.5}$Bi$_{0.5}$TiO$_{3}$ (NBT) was reported as a new family of fast oxygen ionic conductor. We will present our first principles computation study aims to understand the O diffusion mechanisms in the NBT material and to design this material with enhanced oxygen ionic conductivity. Using the NBT materials as an example, we demonstrate the computation capability to evaluate the phase stability, chemical stability, and ionic diffusion of the ionic conductor materials. We reveal the effects of local atomistic configurations and dopants on oxygen diffusion and identify the intrinsic limiting factors in increasing the ionic conductivity of the NBT materials. Novel doping strategies were predicted and demonstrated by the first principles calculations. In particular, the K doped NBT compound achieved good phase stability and an order of magnitude increase in oxygen ionic conductivity of up to 0.1 S cm$^{-1}$ at 900 K compared to the experimental Mg doped compositions. Our results provide new avenues for the future design of the NBT materials and demonstrate the accelerated design of new ionic conductor materials based on first principles techniques. This computation methodology and workflow can be applied to the materials design of any (e.g. Li$+$, Na$+)$ fast ion-conducting materials. [Preview Abstract] |
Thursday, March 17, 2016 9:36AM - 9:48AM |
R54.00007: TiC2: A New Two-Dimensional Sheet beyond MXenes Tianshan Zhao, Shunhong Zhang, Yaguang Guo, Qian Wang MXenes are attracting attention due to their rich chemistry and intriguing properties. Here a new type of metal-carbon-based sheet composed of transition metal centers and C2 dimers rather than individual C atoms is designed. Taking the Ti system as a test case, density functional theory calculations combined with a thermodynamic analysis uncover the thermal and dynamic stability of the sheet, as well as a metallic band structure, anisotropic Young's modulus and Poisson's ratio, a high heat capacity, and a large Debye stiffness. Moreover, the TiC2 sheet has excellent Li storage capacity with a small migration barrier, a lower mass density compared with standard MXenes, and better chemical stability as compared to the MXene Ti2C sheet. When Ti is replaced with other transition metal centers, diverse new MC2 sheets containing C$=$C dimers can be formed, the properties of which merit further investigation. [Preview Abstract] |
Thursday, March 17, 2016 9:48AM - 10:00AM |
R54.00008: Diffusion of lithium in titanium oxide Patrick Shea, Jianchao Ye, Brandon Wood, Stanimir Bonev Titanium oxide has generated interest lately as a promising anode candidate for use in lithium-ion batteries. ~We report first principles calculations on the mobility of lithium atoms in both crystalline and amorphous phases of titanium oxide. ~Density functional theory calculations of structural properties and diffusion energy barriers are combined with rate theory and a lattice gas model to study diffusion of lithium over a range of concentrations. ~A summary of results, including significant differences in the mobility between amorphous and crystalline phases, will be presented and discussed. [Preview Abstract] |
Thursday, March 17, 2016 10:00AM - 10:12AM |
R54.00009: Computational modeling of the structure and the ionic conductivity of the solid electrolyte materials Li$_3$AsS$_4$ and its Ge substitutions Ahmad Al-Qawasmeh, N. A. W. Holzwarth Oak Ridge National Laboratory (G. Sahu et al.)\footnote{J. Matter. Chem. A. 2014, {\bf{2}}, 10396} reported that the substitution of Ge into Li$_3$AsS$_4$ leads to the composition Li$_{3.334}$Ge$_{0.334}$As$_{0.666}$S$_4$ with impressively high ionic conductivity . We use ab initio calculations to examine the structural relationships and the ionic conductivity mechanisms for pure Li$_3$AsS$_4$, Li$_{3.334}$Ge$_{0.334}$As$_{0.666}$S$_4$, and other compositions of these electrolytes. [Preview Abstract] |
Thursday, March 17, 2016 10:12AM - 10:24AM |
R54.00010: Kinetics and Mechanism of Proton Transfer in Molten Lithium Carbonate: Insights from Static and Dynamic DFT Studies Xueling Lei, Kevin Huang, Changyong Qin Using static and dynamic DFT methods and a cluster model, the mechanism and kinetics of proton transfer in lithium molten carbonate (MC) were investigated. The migration of proton prefers an inter-carbonate pathway with an energy barrier of 8.0 kcal/mol. At TS, a linkage of O---H---O involving O 2p and H 1s orbitals is formed between two carbonate ions. It is noticeable that the solvation of proton in an ionic liquid is beyond the capacity of a simple cluster model and that the FPMD method is more suitable for such a molecular system. Corrections on the calculated energies using an extracted cluster were performed and the results displayed good consistency with the value of 7.6 kcal/mol and 7.8 kcal/mol from experiment and FPMD simulation, respectively. The calculated trajectory of H indicates that proton has a good mobility in MC, while both carbon and oxygen only move slightly to facilitate the proton migration. Small geometric variations were observed on all involved ions, not just on the local structure where the proton transfer occurs, implying a synergetic process. A better description of this synergetic step can be displayed in the Lewis diagram. Overall, the results indicate that the combination of the static and dynamic DFT methods is of great advantages in treating such ionic liquid systems and can improve the reliability of the calculated results. [Preview Abstract] |
Thursday, March 17, 2016 10:24AM - 10:36AM |
R54.00011: A formalism for modeling solid electrolyte/electrode interfaces using first principles methods Nicholas Lepley, Natalie Holzwarth We describe a scheme based on the interface energy for analyzing interfaces between crystalline solids, quantitatively including the effect of lattice strain. This scheme is applied to the modeling of likely interface geometries of several solid state battery materials including Li metal, Li$_3$PO$_4$, Li$_3$PS$_4$, Li$_2$O, and Li$_2$S. We find that all of the interfaces in this study are stable with the exception of Li$_3$PS$_4$/Li. For this chemically unstable interface, the partial density of states helps to identify mechanisms associated with the interface reactions. We also consider the case of charged defects at the interface, and show that accurately modeling them requires a careful treatment of the resulting electric fields. Our energetic measure of interfaces and our analysis of the band alignment between interface materials indicate multiple factors which may be predictors of interface stability, an important property of solid electrolyte systems. [Preview Abstract] |
Thursday, March 17, 2016 10:36AM - 10:48AM |
R54.00012: Hexagonal BC${_3}$ as a Robust Electrode Material for Li, Na, and K Ion Batteries Rajendra Joshi, Burak Ozdemir, Juan Peralta, Veronica Barone We propose hexagonal BC${_3}$ as a robust electrode material for Li, Na, and K ion batteries based on first-principles density functional theory calculations. We show that, by intercalating Li, Na, and K in BC${_3}$, it is possible to form Li$_{1.5}$BC${_3}$, Na$_{1}$BC${_3}$, and K$_{1.5}$BC${_3}$ which correspond to a high theoretical capacity of 858 mA h/g, 572 mA h/g, 858 mA h/g, respectively. In addition, this material presents small open circuit voltage variations of 0.49, 0.12, and 0.16 V when used as electrode for Li, Na, and K ion batteries, respectively. [Preview Abstract] |
Thursday, March 17, 2016 10:48AM - 11:00AM |
R54.00013: Computational Investigation of Chevrel Phase Cathodes for Ca$^{\mathrm{2+}}$ Ion Batteries Manuel Smeu While batteries employing Li ions are best suited for applications were portability is important, less expensive alternatives may be employed when size and weight are less critical. Batteries utilizing Ca ions have received very little attention to date due to difficulties in identifying adequate anode materials and electrolytes, although advancements have been made on both fronts. If these challenges can be overcome, Ca can offer an abundant and affordable alternative to Li for grid storage and in other applications where portability is not a priority. For such technologies, appropriate cathodes need to be identified that will allow for reversible intercalation of Ca$^{\mathrm{2+}}$ ions and that can provide a desirable voltage. To this end, we investigate the Chevrel phase (CP) compounds Mo$_{\mathrm{6}}X_{\mathrm{8\thinspace }}(X =$ S, Se, Te), which can intercalate Mg$^{\mathrm{2+}}$ and Ca$^{\mathrm{2+}}$, among many other ions. We use density functional theory (DFT) to calculate the voltage profiles of various guest intercalation ions (Mg, Ca, Sr, Ba) in the CP material. The electronic properties of this material will be discussed, along with the capacity and the energetics associated with ions diffusing through the CP structure. This work also offers insights into how the cathode properties may be fine-tuned by carefully selecting its constituents. [Preview Abstract] |
Thursday, March 17, 2016 11:00AM - 11:12AM |
R54.00014: Investigation of ionic transport in sodium scandium phosphate (NSP) and related compounds Kaustubh Bhat, Stefan Bl\"ugel, Hans Lustfeld Sodium ionic conductors offer significant advantages for application in large scale energy storage systems. In this study, we investigate the different pathways available for sodium ion conduction in NSP and calculate energy barriers for ionic transport using Density Functional Theory (DFT) and the Nudged Elastic Band Method [2]. We identify the structural parameters that reduce the energy barrier, by calculating the influence of positive and negative external pressure on the energy barrier [3]. Lattice strain can be introduced by cation or anion substitution within the NASICON structure. We substitute the scandium atom with other trivalent atoms such as aluminium and yttrium, and calculate the resulting energy barriers. Sodium thiophosphate ($\text{Na}_3\text{P}\text{S}_4$) has previously shown about two orders of magnitude higher ionic conductivity than sodium phosphate ($\text{Na}_3\text{P}\text{O}_4$) [4]. We investigate the effect of substituting oxygen with sulphur in NSP. We acknowledge discussions with our experimental colleagues F. Tietz and M. Guin toward this work. [1] Hong, MRB \textbf{11}, 173-182 (1976). [2] Henkelman et al. JCP \textbf{113}, 9901-9904 (2000). [3] Hirschfeld et al. PRB \textbf{84}, 224308 (2011). [4] Hayashi et al. Nat. Comm. \textbf{3}, 856 (2012). [Preview Abstract] |
Thursday, March 17, 2016 11:12AM - 11:24AM |
R54.00015: Effects on the optical properties of titanium dioxide by doping with sulfur Jorge Hernandez Zeledon, James Lewis $TiO_{2}$ is an attractive material for photocatalytic and photovoltaic applications like watter spliting or self cleaning surfaces, but its maximum absorption happens around 4 eV, and the sunlight irradiance peak is between 1.5eV and 3.1eV. In this work we look for the effects of doping $TiO_{2}$ with sulfur, as one way to reduce the gap between the conduction and the valence states, in order to increase the efficiency of Sun light absorption. To modify the optic properties we took the $TiO_{2}$ rutile structure as basis for random substitutions, in which we randomly select some oxygen atoms and we replace them with sulfur, making $TiO{2(1-x)S2x}$ for x = 0.1 and x = 0.25. Here we present our results for the computational calculations of the band gap and absorption as function of concentration. All the process and calculations are made using the FIREBALL software. [Preview Abstract] |
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