Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session RR02: V: Energy Research |
Hide Abstracts |
Sponsoring Units: GERA Chair: Linda E Reichl, University of Texas at Austin Room: Virtual Room 2 |
Tuesday, March 21, 2023 11:30AM - 11:42AM |
RR02.00001: Breakdown of Soft Anharmonic Phonons Heralds Fast Ionic Diffusion in Lithium Argyrodite Jingxuan Ding, Mayanak K Gupta, Carolin Rosenbach, Naresh C Osti, Douglas L Abernathy, Wolfgang G Zeier, Olivier Delaire A fundamental understanding of the atomic structure and dynamics enabling fast ionic transport in solids is essential for the development of next-generation solid-state electrolytes (SSE). Focusing on the promising SSE candidate Li6PS5Cl with argyrodite structure, we resolve the coupling between fast diffusion of Li+ and vibrational dynamics of the host framework through extensive inelastic and quasielastic neutron scattering measurements, combined with machine-learned molecular dynamics (MLMD) simulations based on first-principles data. Our results establish that host lattice vibrations enable an order-of-magnitude increase in Li+ diffusivity at ambient temperature. Our experiments and simulations both show a clear overlap and interplay of hopping dynamics and vibrational frequencies in the terahertz regime, with a continuous spectral evolution from harmonic phonons to strongly anharmonic overdamped vibrations, and fast Li+ diffusion. We identify the key degrees-of-freedom enabling fast Li diffusion as low-frequency dynamics of PS43- polyanions, which are distinct from the commonly assumed "paddle-wheel" scenario. Bringing together neutron measurements and large-scale MLMD simulations, our results build a "beyond phonons" picture of complex atomic dynamics in SSEs in terms of overdamped spectral functions. These results offer microscopic insights into the mechanism of fast Li+ diffusion in lithium argyrodites and provide guidance for the design of future SSE materials. |
Tuesday, March 21, 2023 11:42AM - 11:54AM |
RR02.00002: First-principles study of Humboldtine as negative battery electrode Bernardo Barbiellini, Fatemeh Keshavarz, Vasilii Gromov, Atlas Noubir, Marius Kadek, Arun Bansil, Ekaterina Laakso We discuss the applicability of the naturally occurring Humboldtine mineral as an anode material. Using first-principles modeling, we evaluate the electrochemical activity of the material and demonstrate how its structural water content affects the intercalation reaction and contributes to its performance. Our analysis indicates that the fully dehydrated ferrous oxalate is a promising anodic material for Li-ion batteries. We also consider Na-ion batteries and we compare the two types of ions. |
Tuesday, March 21, 2023 11:54AM - 12:06PM |
RR02.00003: Defects and Dopants in graphene: Quantum Capacitance and Thermoelectric properties Ramakrishna Podila, Shailendra Chiluwal, Bipin Sharma, Alan Rowland The semi-metallic nature of pristine graphene with very low density of electronic states (DOS) at the Fermi level results in poor thermoelectric properties and a low quantum capcitance. The introduction of defects and dopants in graphene leads to configuration dependent changes in DOS. We prepared defected graphene using chemical vapor deposition and Ar ion irradiation. By using Raman spectroscopy, electrochemistry, and thermoelectric measurements, we will show that quantum capacitance of graphene is highly sensitive to the configuration of dopants. Thermoelectric properties of graphene also show significant changes with different types of defects and dopants. Our experimental observations will be discussed along with density functional theory calculations. |
Tuesday, March 21, 2023 12:06PM - 12:18PM |
RR02.00004: Biphenylene for efficient electrochemical renewable energy conversion. Radha N Somaiya, Muhammad Sajjad, Asha Yadav, Nirpendra Singh, Aftab Alam Excessive consumption of fossil fuels leads to increased CO2 levels in the earth’s atmosphere, which is a serious environmental concern. In the past few decades, there has been an increasing demand to fabricate advanced electrocatalyst for renewable energy conversion. Biphenylene (BPH) has attracted lot of attention to explore as promising advanced electrocatalyst. BPH is metallic in nature with an n-type Dirac cone at/around 0.63 eV above the Fermi level. Like graphene, BPH is also inert to various catalytic processes like CO2 reduction (CRR), N2 reduction (NRR), hydrogen evolution reaction (HER) etc. In this talk, I will present various strategies like vacancy creation, heterovalent doping etc. which can help in better selectivity of efficient catalysts. When N2 is captured on single vacancy, it prefers end-on over the side-on mode giving a binding energy of -2.590 eV. Creation of single vacancy defects unveils its better selectivity towards N2, with acceptable energy barriers at the potential determining step. Copper decorated pristine- and defected-BPH at the preliminary stage indicates its possible application in CRR. This work brings new insights in understanding the defect/doping driven electrocatalytic mechanism in BPH, and facilitates a potential paradigm in designing carbon-based electrocatalysts. |
Tuesday, March 21, 2023 12:18PM - 12:30PM |
RR02.00005: Magnetic spectroscopy signatures in hard-x-ray photoemission of photocatalytic materials for green hydrogen production Tarnjit Kaur K Johal The idealist’s dream of an abundant and clean energy fuel, has long motivated photocatalytic materials research for the production of green hydrogen. While the underlying mechanism for photocatalysis has yet to be definitively understood, maximized light harvesting properties, optimized charge transfer, long lifetimes of intermediate species for redox reactions at the solid/water interface and, in a variety of materials systems, the presence of delocalized spin-states, have been inferred to improve photocatalytic efficiency. In this work we explore the predictive strategies of ensemble machine learning models for inverse modeling of experimental data and density functional theory calculations for inverse materials design. Spectroscopic signatures, in x-ray absorption, photoemission and x-ray emission, have long informed the underlying nature of electronic and magnetic structure. To directly reveal the geometric, electronic and magnetic structure of multifunctional photocatalytic candidate material systems, a formalism for the variation in the photoemission angular distribution in the magnetic linear dichroism geometry, when the excitation photon energy traverses through the crystallographic Bragg condition, is presented. Large synthetic datasets have been generated and served as training datasets for a deep learning model which is tested against the ground truth - experimental data. |
Tuesday, March 21, 2023 12:30PM - 12:42PM |
RR02.00006: First-principles Study of H2 Adsorption Mechanism on Defective MoSe2/Graphene Heterostructures Wadha Al Falasi Transition metal di-chalcogenide monolayers (TMD-MLs), a novel class of the 2D materials, exhibit tremendous properties, such as their tuneable band gap, high surface to volume ratio, appropriate carrier mobility, large spin-orbit coupling and thermal stability, which make this class of 2D-materials a promising leading candidate for many applications. In the present work, the spin-polarised density-functional theory (DFT) is applied to investigate the adsorption of hydrogen-gas molecules on six different adsorbents: (1) MoSe2 ML with single vacancy of Mo “MoSe2:VMo ML”; (2) Mn-doped MoSe2 ML at Mo/Se site “MoSe2:Mn ML”; (3) MoSe2:VMo/graphene hetero-structure; and (4) MoSe2:Mn/graphene hetero-structures. The hydrogen molecule is found to interact in different ways depending on the adsorbents diverse band structures and magnetizations. The MoSe2:VMo/graphene hetero-structure showed the highest adsorption energy of -0.41 eV, but the hydrogen molecule exhibits chemisorption associated with a dissociation which qualify it for gas sensing applications. Moreover, Mn substitutional doping at Se site stands prone as the best candidate for H2 storage. The H2 molecule can be spontaneously adsorbed on top of Mn site with Eads = -0.28 eV. The desorption is shown to cost an energy of about 0.36 eV. Furthermore, the uptake capacity can further be enhanced by increasing the doping concentration of Mn (e.g., MoSe2:2Mn@2Se was tested and found to reach 2.9% wt). |
Tuesday, March 21, 2023 12:42PM - 12:54PM |
RR02.00007: Ultralow lattice thermal conductivity of Gr/h-BN heterostructure using controlled twist engineering Shivani Rani, Soumya J Ray Two-dimensional nanomaterials like graphene and hexagonal boron nitride (h-BN) offer superior electronic properties for future nanoelectronics [1], spintronics [2] and energy applications. When the two materials are combined together to form a van der Waals heterostructure [3], the resulting material offers novel thermal characteristics. In this work, we focus on the electronic, and thermoelectric properties of the Gr/h-BN van der Waals heterostructure in the presence of various twisting angles using on the First-principles based calculations. To sustain the structure stability, we have studied the optimized rotation angles, namely q = 0o, 16.10o, 21.79o, 38.21o, 43.90o and 60o. The material changes from semi-metallic to semiconducting nature at 21.79o and 38.21o twisting angles, respectively. Using semiclassical Boltzmann transport approach, Seebeck coefficient, electrical conductivity and power factor at twist angles of 0o, 21.79o, 38.21o, and 60o are found to be much higher than the other configurations. Moreover, at the 60o twisting angle, the Power Factor in the n-type dopants can reach upto 1.37×1011 W/msK2. The lattice thermal conductivity at room temperature is found to be very low in 16.10o, 21.79o, 43.90o and 38.21o rotation angles. An ultralow lattice thermal conductivity with a value of 0.095 W/m K at 300K has been observed for 21.79o rotation angle, which is lower than our other rotation angles because of the very low group velocity (22.1 ×103 Km/s) and short phonon lifetime (0.18 ps) at 21.79o angle. The high thermoelectric performance results from an ultralow thermal conductivity arising due to the strong lattice anharmonicity. These results can have a significant impact on the synthesis of high performance thermoelectric materials based on twisted Gr/h-BN heterostructure. |
Tuesday, March 21, 2023 12:54PM - 1:06PM |
RR02.00008: Nanoscale Bolometry: Pushing Sensitivity Limits of Uncooled Infrared Thermal Detectors Ethan A Scott, Ting S Luk, Oleg Mitrofanov, Peter A Sharma, Tzu-Ming Lu, Charles T Harris Resistive bolometers are devices that change resistance in response to a change in temperature. Often, they are used in the thermal detection of infrared radiation through the incorporation of an absorbing film that transduces absorbed light into a rise in temperature. The performance of these devices may be quantified by specific detectivity, which is fundamentally limited by how well the device is radiatively coupled to its environment. In this presentation, we discuss experimental efforts toward the realization of an uncooled bolometer with performance approaching the theoretical limit of detectivity. Among these efforts, we highlight advancements in the development of critical device elements including high-efficiency, ultra-thin absorber and thermometer films. In addition, we discuss a nanofabrication method to suppress thermal conductance due to conduction and enhance the radiant heat exchange of the system. |
Tuesday, March 21, 2023 1:06PM - 1:18PM |
RR02.00009: Tin oxide graphene system for law terahertz near field radiation modulation Desalegn Tadesse Debu, M. Hasan Doha, Qigeng Yan, Ermias A Kassaye We propose a graphene and hyperbolic materials introduced tin oxide (SnO2) to theoretically study gate modulation of near-field thermal radiation at law terahertz. Compared with blackbody result, the near field heat transfer is significantly enhanced due to graphene plasmon and hyperbolic phonon polariton modes of SnO2. In law terahertz range the near field radiation transfer show film thickness. Highly enhanced heat transfer was obtained for law graphene chemical potential ( |
Tuesday, March 21, 2023 1:18PM - 1:30PM |
RR02.00010: The role of surface energy in propagation of stress-induced cracks in Li-intercalated micro hollowsphere silicon anodes - the forward lithiation process Tejveer S Anand, Jayant Choudhary, Henam Sylvia Devi, Madhusudan Singh Due to the promisingly high theoretical capacity to incorporate substantial amounts of lithium, silicon anodes in lithium-ion batteries experience high degrees of volumetric changes during cycling, leading to battery failure and capacity fading due to pulverization and fracture of the anode material. In this work, an analytical model based on the concentration-driven reaction-diffusion equation for concentration and linear elasticity has been developed to study the time-evolution of all significant stresses: radial, hoop, and hydrostatic, under the forward lithiation process, in a unified model. This model combines diffusion-induced stress (DIS), reaction-induced stress (RIS), and surface effects coupled with multiple functional parameters at low Li concentrations at the outer surface of the hollow silicon sphere under potentiostatic operation. In our study, the dynamic stoichiometric ratio of Li in Li-Si alloy was used to interpolate Young's modules and further incorporated in BOLS theory to obtain the cumulative effect. To illustrate the importance of surface effects, we used analytical solutions to the coupled problem in spherical geometry to study a hollow sphere with an inner and outer radius of 200 and 500 nm, respectively. When the aforementioned surface effects are considered, radial stress at the outer boundary of the sphere reaches -4 MPa, leading to the stress becoming compressive. Similarly, its value closer to the mid-center of the shell thickness (~350 nm) shows 0.81 MPa without surface effects, whereas it becomes compressive with surface effects, reaching approximately -2.31 MPa. With a systematic increase in surface energy parameters, radial and hoop stress at the external interface becomes more compressive. Additionally, it is observed that the RIS plays a dominant role over the DIS in a coupled system; thus, as the intercalation reaction progresses, the maximum peak of radial stress increases. In the analysis, we have discovered the significance of a figure of merit in determining the impact of RIS on the nature of hoop stress at the outer surface. We are currently studying the effects of a more suitable model for time-dependent boundary conditions for the rational design of anodes under plastic deformation during cycling, including the potential of machine learning methods. |
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