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 F45: Energy - Lithium Battery Cathodes and Anodes |
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Sponsoring Units: GERA Chair: Venkata Surya Chaitanya Kolluru, Argonne National Laboratory Room: Room 315 |
Tuesday, March 7, 2023 8:00AM - 8:12AM |
F45.00001: Understanding Charge Transport and Storage Mechanisms in Electrochemical Energy Storage Devices using in Operando Small Angle Neutron Scattering Lilin He Rechargeable batteries and electrochemical supercapacitors are two of the most promising technologies to power mobile electronics, electric vehicles and large-scale grid storage. These techniques are facing some issues, i.e. cost, safety, cycle life, energy and power density, that hinder their applications, especially in transportation and stationary electrical energy storage. Molecular-level understanding of transport and storage mechanisms of electrolyte ions in electrodes and electrolyte solutions under operating electrochemical conditions is essential to design next generation materials. Small angle neutron scattering (SANS) has become an indispensable tool to provide key insights across length scales from 1 to 200 nm and kinetics on time resolution spanning from seconds to hours. This technique benefits from the adjustable contrast via deuteration of solvents or electrolytes; non-destructive due to the high penetrating power of neutrons. It also provides statistically meaningful measurements over the total volumes of illumination within complex sample environments and functional devices under varying experimental conditions. In this talk, I will highlight the applications of SANS in the characterization of electrodes and electrolytes in the past decade. The limits and future development direction of this technique for the operando characterization are also discussed. |
Tuesday, March 7, 2023 8:12AM - 8:24AM |
F45.00002: Suppression of dendrite growth with multiple charging modes for fast charge Lithium metal anode using the Lattice Boltzmann Method Zhuolin Xia, Dilip Gersappe Dendrite growth on the anode surface is a critical challenge in developing reliable Lithium metal batteries. Even though numerous strategies have been reported to regulate Li deposition, a more fundamental understanding of electrodeposition process and a more systematical study of the impacts of charging conditions are needed. To accomplish these, we developed a 3D model using the Lattice Boltzmann Method to simulate charging processes under various charge modes. The model takes account of the effects of charge current/potential and morphological features on the local ion concentration and morphology evolution. We first studied the dendrite formation under simple constant current(CC) and constant voltage(CV) charging protocols. The results show that dendrite form upon ion depletion and dendrite morphologies are associated with anode surface heterogeneity and potential divergence. We then incorporated charge patterns including constant current-constant voltage(CC-CV), constant current-pulse voltage(CC-PV), constant current-pulse current(CC-PC) and constant current-pulse current with constant current(CC-PVCC) charge. CC-CV mode is effective in suppressing dendrite growth when we choose appropriate preset voltage for switching from CC to CV mode. CC-PVCC has the best performance among pulse modes for achieving dendrite-free anode with optimal charge time. |
Tuesday, March 7, 2023 8:24AM - 8:36AM |
F45.00003: Ab-Initio Accuracy at Unprecedented Length and Time Scales for Lithium Metal Simulations using Machine Learning Keith K Phuthi The mechanical properties of lithium metal are key parameters in the design of next generation lithium metal batteries. They are difficult to probe experimentally due to the high reactivity and low melting point of lithium as well as the microscopic scales at which lithium exists in batteries where it is found to have enhanced strength, with implications for dendrite suppression strategies. Computationally, there is a lack of good empirical potentials and Ab-Initio calculations are too costly. In this work, we generate data and train two Machine Learning Interaction Potentials (MLIPs) with Density Functional Theory (DFT) data to state-of-the-art accuracy in reproducing experimental results. Using Molecular Dynamics (MD), we predict a number of thermal and mechanical properties of lithium and their temperature dependence. |
Tuesday, March 7, 2023 8:36AM - 8:48AM |
F45.00004: Ionic Current in Lithium-Ion Batteries during Rest after Fast Charging Alec Ho, Nitash P Balsara Reducing electric vehicles charging time is essential to alleviate range anxiety and expand mass market adoption. Fast charging of Li-ion batteries is hindered by lithium plating on the graphite electrode, which is detrimental to cell performance and safety. In addition, some Li-ion batteries can explode in an electric vehicle even the electric vehicle is not being charged or discharged. Lithium plating that occurs during fast charging can reintercalate into the graphite during rest. However, this process has not been studied in three dimensions. |
Tuesday, March 7, 2023 8:48AM - 9:00AM |
F45.00005: Highly oxidized states of oxide-based battery cathodes Wanli Yang The improvement of energy density of electrochemical energy storage devices, i.e., batteries, is bottlenecked by transition-metal (TM) oxide based cathodes. At this time, the very first generation of oxide cathode, LiCoO2, remains the choice for the record-high energy density accessible in practical batteries after more than three decades of intensive efforts. It is clear that conventional concepts have to be innovated, and the selection and optimization of oxide-based components in energy applications need to be guided by fundamental understandings. In this talk, we will first explain that pushing a rechargeable battery system into the high-energy operation always spontaneously triggers a highly oxidized oxide state in the battery cathode during high voltage charging. The highly oxidized TM oxides is a complex system, in which conventional ionic crystal models fail and a significant amount of oxygen activities are involved in the electrochemical operations, the so-called oxygen redox reaction. We show that soft X-ray resonant inelastic X-ray scattering (RIXS) is a powerful tool for detecting and distinguishing different types of oxygen activities; however, reliable experimental data indicate a very complex nature of these highly oxidized states of oxide cathodes, which calls for collaborations in Physics, Chemistry and Material Science scientists to tackle the fundamental understanding and practical optimization of highly oxidized oxide systems towards high energy-density batteries. |
Tuesday, March 7, 2023 9:00AM - 9:12AM |
F45.00006: Oxygen reaction activities in battery materials Li2MO3 studied through resonant inelastic soft x-ray spectroscopy (RIXS) Zengqing Zhuo, Wanli Yang, Jinghua Guo Recent clarification through high efficiency mapping of resonant inelastic X-ray scattering (mRIXS) have revealed that, oxygen reaction activities are distinctive among the three representative Li-rich parent compounds, Li2MO3 (M=Mn, Ru, Ir), i.e., only irreversible oxygen oxidation reaction for Mn (3d) system, separate reversible Ru and O redox reactions for Ru (4d) system, and only divalent cationic redox reaction for Ir (5d) systems. Here, through quantification of transition metal redox and characterizations of the lattice oxygen state, we finally provide a direct comparison among the three representative Li2MO3 compounds. Firstly, Li-rich configuration does not naturally trigger reversible oxygen redox, as there is no oxygen redox observed in Mn and Ir systems. It indicates that extra critical TM factors are required to maintain the reversible oxygen redox. Secondly, compared with Ru and Ir systems with both Ru/O redox involved and only Ir redox involved, separately, it indicates that oxygen redox is not necessarily enabled until the Li extraction amount which cationic redox could compensate is exhausted. Thirdly, comparison between irreversible oxygen oxidation process in Li2MnO3 and the high reversible oxygen redox activities in Ru systems, suggests the critical role for stabilization effect of TMs-O hybridization in oxygen activities, which has been emphasized in the ground-breaking works of the oxygen redox but got largely overlooked later. This work suggests the important role of transition metals and their coupling and hybridization effect to oxygen for maintaining reversible oxygen redox activities. |
Tuesday, March 7, 2023 9:12AM - 9:24AM |
F45.00007: First-principles investigation of Al2O3 cathode coatings on Co and Ni-rich cathodes M.D. Hashan C Peiris, Manuel Smeu We investigate the characteristics of atomic layer deposited (ALD) Al2O3 on LiCoO2 cathode surfaces (LCO) using density functional theory and ab initio molecular dynamics (AIMD). The cathode+coating+electrolyte interfaces are simulated with varied Co-rich cathode orientations, lithiation, and the thickness of the coating. Organic electrolytes were explicitly modeled, composed of ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1), while LiBF4 was included as a salt. We observe a more pronounced decomposition of electrolyte molecules on delithiated systems relative to lithiated surfaces and the initial signs of the formation of cathode-electrolyte interphase. Molecular O2 had more propensity to evolve from the exposed cathode (012) surface, while it was more uniform for coated surfaces. Dehydrogenation of electrolyte molecules close to the exposed surface was more prevalent. O2 formation within the cathode-coating interface was observed for the (012) surface. Charge analysis using the DDEC6 method revealed that the coating of the cathode consistently preserves the charge of surface Co atoms closer to the charge of bulk Co, otherwise significantly different on the exposed side. We also report on the mechanisms of ALD deposition of Al2O3 on Ni-rich cathodes. Our work highlights the applicability of combining AIMD and DFT approaches to guide the design of innovative cathode coatings. |
Tuesday, March 7, 2023 9:24AM - 9:36AM |
F45.00008: Modeling intercalation chemistry with multiple redox reactions by sparse lattice model Peichen Zhong, Fengyu Xie, Gerbrand Ceder Disordered rocksalt materials are the most promising earth-abundant cathode materials for Li-ion batteries, and as such can enable scaling of Li-ion energy storage to many TWh/year production. Such modern battery materials can contain a large number of elements with substantial site disorder, and their state of short-range ordering has been shown to be critical for their performance. Ab-initio modeling of the configurational degrees of freedom increases exponentially with the number of species included. The problems to apply cluster expansion techniques include: (1) how to generate lattice models without over-fitting; (2) how to properly sample the configurational space in ionic systems with charge-neutrality. |
Tuesday, March 7, 2023 9:36AM - 9:48AM |
F45.00009: Evaluating Factors Affecting Li-ion Diffusivity in Ru-dopped LiFePO4 Bhubnesh Lama, Alevtina L Smirnova, Tula R Paudel Ionic diffusivity plays a central role in the performance of the battery materials. We use molecular dynamics simulation based on on-the-fly machine learning potential to show that Li-ion diffusivity in well-known cathode lithium iron phosphate (LFP) increases when doped with transition metal dopant Ru. Our finding corroborates pertinent literature showing improved electrochemical performance of LFP upon Ru doping. This increment is accompanied by changes in lattice and its electronic properties, including reduction of lattice in the diffusion direction, appearance of defect states in the middle of band gap and vicinity of the conduction band, and reduction in Li-diffusion barrier. Our calculation informs parameters that affect ionic diffusivity in LFP, which may be used for machine learning-based materials design protocols. |
Tuesday, March 7, 2023 9:48AM - 10:00AM |
F45.00010: Accurate electronic properties and intercalation voltages of Li-ion cathode materials from extended Hubbard functionals Iurii Timrov, Francesco Aquilante, Matteo Cococcioni, Nicola Marzari The design of novel cathode materials for Li-ion batteries requires accurate first-principles predictions of their properties. Density-functional theory (DFT) with standard (semi-)local functionals fails due to the strong self-interaction errors of partially filled d shells of transition-metal elements. Here, we perform a detailed comparative study of the phospho-olivine cathode materials using four electronic-structure methods: DFT, DFT+U, DFT+U+V, and HSE06. We show that DFT+U+V, with onsite U and intersite V Hubbard parameters determined from first-principles and self-consistently with respect to the structural parameters by means of density-functional perturbation theory (linear response), provides the most accurate description of the electronic structure of these challenging compounds. In particular, we demonstrate that DFT+U+V displays clearly "digital'' changes in oxidation states of the transition-metal ions in all compounds, including the mixed-valence phases occurring at intermediate Li concentrations, leading to voltages in remarkable agreement with experiments. We thus show that the inclusion of intersite Hubbard interactions is essential for the accurate prediction of thermodynamic quantities. |
Tuesday, March 7, 2023 10:00AM - 10:12AM |
F45.00011: Sulfurized Polymer Cathodes for Li-S batteries: Mechanisms, Misconceptions, and Metrics Alan Rowland, Nawraj Sapkota, Shailendra Chiluwal, Prakash Parajuli, Ramakrishna Podila Lithium–sulfur (Li-S) battery are a promising candidate for electrical energy storage. Beyond elemental sulfur electrodes, many researchers proposed sulfurized polymers (SP) for circumventing polysulfide formation and achieving long cycling stability and high C-rate performance. However, practical application of SP electrodes are often written off due to their low S loading (~35 wt. %). In this talk, we will show that SP electrodes function as hybrid supercapacitors with carbon backbone contributing to the total capacity using a comprehensive array of tools including in situ electrochemical Raman spectroscopy. Based on our results, we address the following fundamental questions in Li-SP electrochemistry that are critical for industrial translation: 1) Are the critical metrics for S8/C cathodes (which consider carbon to be dead weight) relevant for SP cathodes? 2) Does the superior performance of N-containing SP result from the alleviation quantum capacitance? 4) Are SP with S content >35 wt. % fundamentally unstable? 4) If stability of SP is limited to ~35 wt. %, how can practical S-loadings >5 mg/cm2 be achieved? 5) In case of “active” carbon skeleton, does the practical realization still require high S content ~70 wt. % in SP cathodes? |
Tuesday, March 7, 2023 10:12AM - 10:24AM |
F45.00012: Sulfurized Polymer Cathodes for Li-S batteries: Mechanisms, Misconceptions, and Metrics Alan Rowland, Nawraj Sapkota, Shailendra Chiluwal, Ramakrishna Podila, Prakash Parajuli Lithium–sulfur (Li-S) battery are a promising candidate for electrical energy storage. Beyond elemental sulfur electrodes, many researchers proposed sulfurized polymers (SP) for circumventing polysulfide formation and achieving long cycling stability and high C-rate performance. However, practical application of SP electrodes are often written off due to their low S loading (~35 wt. %). In this talk, we will show that SP electrodes function as hybrid supercapacitors with carbon backbone contributing to the total capacity using a comprehensive array of tools including in situ electrochemical Raman spectroscopy. Based on our results, we address the following fundamental questions in Li-SP electrochemistry that are critical for industrial translation: 1) Are the critical metrics for S8/C cathodes (which consider carbon to be dead weight) relevant for SP cathodes? 2) Does the superior performance of N-containing SP result from the alleviation quantum capacitance? 4) Are SP with S content >35 wt. % fundamentally unstable? 4) If stability of SP is limited to ~35 wt. %, how can practical S-loadings >5 mg/cm2 be achieved? 5) In case of “active” carbon skeleton, does the practical realization still require high S content ~70 wt. % in SP cathodes? |
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