bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Hydrogenation of Refractory Organic Pollutants for Wastewater Treatment
Authors: Shao Shan , Lam Jason Chun-Ho
Published: August 2024

Wastewater treatment is an essential process for the sustainable development of a society. The handling and degrading of different refractory and toxic organic pollutants heavily relies on conventional biodegradation. Herein, we developed an electrochemical hydrogenation method to enhance the biodegradability of organic substrates, which subsequently improves their availability to existing biological-driven denitrification, a key step that turned NO3
- into harmless N2. The strategy presents an unprecedented "kill-two-birds-with-one-stone" method to simultaneously deal with excessive organic components, aka. Chemical Oxygen Demand (COD), and nitrate's presence in wastewater. The strategy was discovered by comparing the biodegradability of some organic compounds and their hydrogenation forms. It was found that the hydrogenation product was much more bioavailable. Motivated by this discovery, we synthesized a carbon-supported Ru electrode by electrodepositing Ru on activated carbon cloth (ACC), named Ru/ACC. After that, 4-chlorophenol was used to optimize the experimental conditions, and Ru/ACC electrodes successfully converted 99.9% of 4-chlorophenol with an overall yield reached 90.9%. After that, the Ru/ACC electrodes proved efficient in transferring various wastewater organic pollutants. Besides, the electrochemical hydrogenation effect on biochemical degradation and denitrification was studied. Our electrochemical treatment was significant for the electrochemical hydrogenation method to be applied to wastewater treatment.
Understanding the Phase Evolution and Charging Mechanism in Dual Cation Cathodes
Authors: Choi Yunyeong , Ceder Gerbrand
Published: August 2024

Multivalent batteries offer potential advantages over lithium-ion batteries but face challenges due to limited ionic mobility in solid-state cathodes. Recent investigations have demonstrated that incorporating multivalent cations, particularly calcium ions (Ca2+), into monovalent cathodes such as NaSICON and R-3m NaV2(PO4)3, results in improved capacity retention. This study investigates the phase evolution and charging mechanism in these dual cation cathodes by using a cluster expansion and charge-neutral Monte Carlo simulation in a Ca-Na-V2(PO4)3 system. Our results found that during the discharge with either Ca or Na ions, phase transitions occurs when the oxidation state of the transition metal changes, in particular between Na1V2(PO4)3 - Na3V2(PO4)3 and Na1V2(PO4)3 - Ca1V2(PO4)3. This behavior suggests that the charging pathway of Na/Ca ions can be altered by varying the Ca/Na chemical potential.

Figure 1
Proton Transport in Aqueous Phosphoric, Sulfuric, and Nitric Acids: An Ab Initio Study
Authors: Zhu Zhenghao , Popov Ivan , Sokolov Alexei P. , Paddison Stephen J.
Published: August 2024

Proton transport plays a pivotal role in various electrochemical processes and technologies. It occurs through two primary mechanisms: the vehicular mechanism where a protonic defect moves with the aid of a molecular entity; and the ‘Grotthuss mechanism’ where a proton diffuses by being transferred between host molecules via hydrogen bonds. Recently, results from ab initio molecular dynamics (AIMD) simulations combined with dielectric spectroscopy, light, and quasielastic neutron scattering revealed that protons in neat phosphoric acid indeed move by surprisingly short jumps (~0.5-0.7 Å)1,2. In the present work, we continue to delve into the solvation and transport of protons in aqueous acid using AIMD simulations.

Aqueous systems of phosphoric acid (PA), sulfuric acid (SA), and nitric acid (NA) were examined at two different ratios of acid to water 1:1 and 1:3 to understand the similarities and differences in proton transport mechanisms in these aqueous acids. The solvation structure of H3O+ in these acid solutions resembles that in the slightly acidic water but varies in the strength of hydrogen bonds formed with the acid molecules. Our results demonstrate that the strong hydrogen bonds between the PA molecules are slightly influenced by the presence of water molecules. Furthermore, the simulations reveal that H3O+ diffuses significantly faster in the aqueous PA systems than in the solutions of either SA or NA due to the assistance of PA molecules. Proton transfer events in the process of H3O+ transport show that the acid molecule can accept a proton from H3O+, either enhancing the H3O+ diffusion by shuttling a proton through a collective proton hopping or impeding it via rattling. The shuttling event significantly contributes to the H3O+ diffusion in aqueous PA, rarely occurring in the aqueous SA and never in the aqueous NA. Moreover, decomposition of H3O+ diffusion into vehicular and structural diffusion components indicates that the higher diffusion in aqueous PA is primarily due to the structural mechanism aided by the PA molecules. In the aqueous NA systems, however, the vehicular diffusion is dominant at low water contents, while increasing water content enhances the structural diffusion via connected hydrogen bonds between the water molecules. These findings shed light on the role of acid molecules in proton transport within their aqueous solutions, advancing our understanding of these fundamental mechanisms.

References:

Popov, I., Zhu, Z., Young-Gonzales, A.R., Sacci, R. L., Mamontov, E., Gainaru, C., Paddison, S. J., and Sokolov, A. P. Search for a Grotthuss Mechanism through the Observation of Proton Transfer. Commun. Chem.
6, 77 (2023).

Zhu, Z., Popov, I., Sokolov, A. P., and Paddison, S. J. Mechanistic Insights into Proton Transport in Pure and Aqueous Phosphoric Acid,
In ECS Meet. Abstr.
MA2022-02,2178 (2022).
Modeling Interfacial Proton-Coupled Electron Transfer Reactions Involving Imidazolium Proton Donors
Authors: Bagbudar Zeynep , Warburton Robert
Published: August 2024

Proton-coupled electron transfer (PCET) is an elementary reaction that plays a pivotal role in various electrochemical energy conversion and storage processes. PCET reactions involving nonaqueous proton donors are of interest for applications in energy storage such as redox flow batteries, as well as in CO2 and O2 reduction catalysis. Yet, there remains much to be understood about the molecular reactivity of these systems. In this talk, I will describe periodic density functional theory (DFT) studies of interfacial PCET reactions involving different imidazolium proton donors on Pt(111) electrode surfaces.

The imidazole conjugate bases adsorb strongly to the electrode surface; however, this adsorption behavior varies with isomers that feature distinct proton positions and with different functional substituent groups. Because the adsorption of imidazole conjugate bases could affect reactivity, these models are used as a foundation to understand the intrinsic PCET kinetics of these systems. The Volmer and Heyrovsky steps of hydrogen evolution reaction are two of the most basic heterogeneous electrochemical PCET reactions and are therefore chosen as model interfacial PCET reactions in this study. Potential-dependent reaction energies and activation barriers are calculated using the charge extrapolation method, where the electrode potential is tuned by modifying proton coverage for different-sized unit cells. This approach is used to develop relationships between PCET reaction thermodynamics and kinetics through Brønsted–Evans–Polanyi (BEP) relationships for different imidazoles, where BEP slopes are analogs to charge transfer coefficients in the Butler–Volmer equation. Investigating reaction parameters influencing charge transfer kinetics at the electrode-electrolyte interface is crucial for designing efficient energy storage systems, impacting overall device performance. These studies show trends in the kinetic behavior of different functionalized imidazoles, which can aid in the design of catalytic and energy storage systems.
Investigating the Existence of a Pseudo-Initial State in Proton Transfer during the Volmer Reaction in a Grand Canonical Environment
Authors: Kim Juye , Peterson Andrew A.
Published: August 2024

Protons play a significant role in electrochemical reactions. In a simulated Volmer reaction, we can imagine the initial state as a situation where protons are in a bulk state with an empty metal slab. To study the reaction barrier, we need to move the protons from the reservoir to the surface of the electrode. We term the state where the proton has reached the near-surface layer the pseudo-initial state. This prompts the question of how protons from the bulk migrate to the near-surface and whether this pseudo-initial state truly exists. If protons don't become localized at the near-surface layer but follow a concerted mechanism, the existence of the pseudo-initial state becomes uncertain. In our research, we examined the pathways of protons in the grand canonical system using the solvated jellium method and determined the localization of protons in the near-surface layer, thus confirming the existence of pseudo-initial states.
Quantifying Aging-Induced Irreversible Volume Change of Porous Electrodes
Authors: Garrick Taylor R. , Miao Yong , Macciomei Eric , Fernandez Miguel , Weidner John W.
Published: August 2024

Automotive manufacturers are working to improve cell and pack design by increasing their performance, durability, and range. One of the critical factors to consider as the industry moves towards materials with higher energy density is the ability to consider the irreversible volume change characteristic of the accelerated SEI layer growth tied to the large volume change and particle cracking typically associated with active material strain. Here, we add to a previously developed mechano-electrochemical model[1-8] to more practically understand the impact of irreversible volume change, primarily assigned to SEI layer growth. As the time from initial design to manufacture of electric vehicle is decreased in order to rapidly respond to consumer demands and widespread adoption of electric vehicles, the ability to link aging and volume change to end of life vehicle requirements using virtual tools is critical.[9] In this study[10], we apply a model to determine the irreversible volume change at the electrode and cell level, allowing for virtual design iterations to predict the volume change at battery cell aged states, and probe possible changes in the SEI layer over life.

References

1. T. R. Garrick, K. Kanneganti, X. Huang and J. W. Weidner, J Electrochem Soc, 161, E3297 (2014).

2. T. R. Garrick, Y. Dai, K. Higa, V. Srinivasan and J. W. Weidner, ECS Transactions, 72, 11 (2016).

3. T. R. Garrick, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3552 (2017).

4. T. R. Garrick, K. Higa, S.-L. Wu, Y. Dai, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3592 (2017).

5. D. J. Pereira, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 166, A1251 (2019).

6. D. J. Pereira, M. A. Fernandez, K. C. Streng, X. X. Hou, X. Gao, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 167, 080515 (2020).

7. D. J. Pereira, A. M. Aleman, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 169, 020577 (2022).

8. T. R. Garrick, M. A. Fernandez, M. Verbrugge, C. Labaza, R. Mollah, B. J. Koch, M. Jones, J. Gao, X. Gao and N. Irish, J. Electrochem. Soc., 170 060548 (2023)

9. T. R. Garrick, Y. Zeng, J. B. Siegel, and V. R. Subramanian, J. Electrochem. Soc., 170 113502 (2023)

10. T. R. Garrick, Y. Miao, E. Macciomei, M. Fernandez and J. W. Weidner, J Electrochem Soc, 170, 100513 (2023).
Modeling the Impact of Microstructure Variation on Charging Capability in Lithium-Ion Batteries
Authors: Teel Hunter , Garrick Taylor R. , Lopata Joseph Steven , Wang Fengkun , Zhang Han , Zeng Yangbing , Shimpalee Sirivatch
Published: August 2024

Battery models can be used to predict conditions ripe for lithium metal plating in the anode during rapid charging. One common procedure is to simulate a rapid charge using a pseudo-two-dimensional (P2D) model and determine if and when the minimum local potential reaches 0.0 V with respect to metallic lithium in the anode. This normally occurs at higher states of charge during a DC fast charging or rapid regenerative charging event. However, we have recently determined that three-dimensional (3D) models, while broadly agreeing with P2D results, demonstrate much variation in the in-plane and through plane direction, which P2D models cannot resolve. Because P2D models employ effective medium approximations, any “local” value in the P2D space along the through-plane coordinate represents an average across a slice of the domain. Therefore, it may be insufficient to use minimum anode potentials from P2D models as indicators of local plating and may only be representative of global lithium plating onset.

The results of rapid-charge 3D microstructure simulations are compared to P2D results. This allows us to verify whether rapid charging induces negative local potentials at the anode active material surface that are left undetected in a P2D model. The expected result implies that the 3D microstructure model is necessary to predict the onset of lithium plating. We then extend our previous study to look at the impact of design changes on the microstructure performance, and then link the microstructure performance changes to performance metrics at the battery cell, module, pack, and vehicle level. Finally, the impact of variation in the microstructure domain considering particle size variation is quantified to understand tolerances that may be necessary when developing charging schemes.

References:

1. J. S. Lopata, T. R. Garrick, F. Wang, H. Zhang, Y. Zeng and S. Shimpalee, J Electrochem Soc, 170, 020530 (2023).

2. T. R. Garrick, Y. Zeng, J. B. Siegel, and V. R. Subramanian, J. Electrochem. Soc., 170 113502 (2023)
(Keynote) Unified Quantum Theory of Electrochemical Kinetics Based on Coupled Ion-Electron Transfer
Authors: Bazant Martin Z.
Published: August 2024

A general theory of coupled ion–electron transfer (CIET) is presented, which unifies quantum kinetics of electron transfer (ET) with classical kinetics of bond-breaking ion transfer (IT) in a general framework of non-equilibrium thermodynamics [1]. In the limit of large reorganization energy, the theory predicts Marcus kinetics of “electron-coupled ion transfer” (ECIT). In the limit of large ion-transfer energies, the theory predicts generalized Butler–Volmer kinetics of “ion-coupled electron transfer” (ICET), where the charge transfer coefficient and exchange current are connected to microscopic properties of the electrode/electrolyte interface. In the ICET regime, the reductive and oxidative branches of Tafel’s law are predicted to hold over a wide but finite range of overpotentials, bounded by the ion-transfer energies for oxidation and reduction, respectively. The probability distribution of transferring electron energies in CIET smoothly interpolates between a shifted Gaussian distribution for ECIT (as in the Gerischer–Marcus theory of ET) to an asymmetric, fat-tailed Meixner distribution centered at the Fermi level for ICET. The latter may help interpret asymmetric line shapes in x-ray photo-electron spectroscopy (XPS) and Auger electron spectroscopy (AES) for oxidized metal surfaces in terms of shake-up relaxation of the ionized atom and its image polaron by ICET. In the limit of large overpotentials, the theory predicts a transition to inverted Marcus ECIT, leading to a universal reaction-limited current for metal electrodes, dominated by barrierless quantum transitions. Uniformly valid, closed-form asymptotic approximations are derived that smoothly transition between the limiting rate expressions for ICET and ECIT for metal electrodes, using simple but accurate mathematical functions. The theory is applied to lithium intercalation in lithium iron phosphate (LFP) and found to provide a consistent description of the observed current dependence on overpotential, temperature and concentration, learned from x-ray images [2]. CIET theory thus provides a critical bridge between quantum electrochemistry and electrochemical engineering.

[1] M. Z. Bazant, Unified quantum theory of electrochemical kinetics by coupled ion-electron transfer, Faraday Discussions 246, 60-124 (2023).

[2] H. Zhao, H. D. Deng, A. E. Cohen, J. Lim, Y. Li, D. Fraggedakis, B. Jiang, B. D. Storey, W. C. Chueh, R. D. Braatz, and M. Z. Bazant, Learning heterogeneous reaction kinetics from X-ray movies pixel-by-pixel, Nature 621, 289-294 (2023).

Figure 1
A Theoretical Study on Doped-NiOOH Catalysts for Enhanced Urea Oxidation Reaction
Authors: Jin Qiu , Garcia-Ortiz Matteo Xavier , Arnadottir Liney
Published: August 2024

Urea is a common waste specie in agricultural runoff water and has been considered as a promising oxidizable molecule for substitution of oxygen evolution reaction (OER) to save energy. However, the overpotential of electrochemical urea oxidation reaction (UOR) is still high due to the complicated six-electron transfer process on most metal catalysts and the competition with OER further limits catalyst options for UOR. The most promising and studied catalysts for UOR are Ni-based catalysts. Previous theoretical and experimental research works have focused on NiOOH step-edges as active sites for UOR. In this work, we focus on gaining atomic-level insight into the role of basal-type sites in UOR, which represent the largest surface area of NiOOH catalysts. We study the effects of vacancies as well as metal doping on the transformation from Ni(OH)2 to NiOOH active phase and the UOR pathway using density functional theory (DFT) calculations. By investigating various Ni(OH)2 and NiOOH (001) surfaces with vacancies and dopants such as Fe, Co and Cu, we are able to examine how the active sites influence the Ni-catalysts transformation and the urea oxidation. This work sheds light on the structure-property relationship of Ni(OH)2/NiOOH in urea oxidation and offers design principles for functional Ni-based materials, which will help accelerate the development of efficient UOR catalysts.
Destabilization of Oxygen Reduction Reaction Intermediates on a PGM-Free Electrocatalyst By Axial Spectator Ligands
Authors: Clary Jacob , Aubry Taylor , Vigil-Fowler Derek
Published: August 2024

Platinum-group free Fe-N-C catalysts have been shown to be a promising class of electrocatalysts for the oxygen reduction reaction (ORR) in acidic media. However, typical synthesis methods can result in a variety of FeN4 sites embedded in graphene, including bulk-hosted and edge-hosted FeN4. The planar structure of the FeN4 active site allows two additional ligands to adsorb to Fe on either side of the graphene, which can be present from ORR reaction intermediates and other solution phase species. Here, we studied the impact of axially adsorbed ligands on bulk-hosted and edge-hosted FeN4 sites by screening over all pairs of H, O, OH, OOH, O2, H2O, NO, SO4, HSO4, and ClO4 axial ligands using solvated grand canonical density functional theory (GCDFT) to self-consistently account for applied potential. The first axial Fe adsorbate can strongly influence the binding of a second axial adsorbate and increase its adsorption energy by up to 2 eV, with more destabilization occurring for a more positive applied potential and the O* ORR intermediate being affected most. However, GCDFT calculations on these same sites without axial spectator ligands show that O* and OH* are both thermodynamically persistent, suggesting that axial spectator ligands might play a role in explaining this catalyst’s high experimental activity. Additionally, we show how the combined effects of potential, nature of the FeN4 site, and axial ligand impact O2 adsorption favorability and availability of sites in the presence of competing molecules. This work highlights the need for the continued development of advanced electrocatalyst models that account for a wide range of active site structures to facilitate comparison with experiment.
Beam Effects in Synchrotron Radiation Based Operando Characterization of Battery Materials: XRD and XAS Study of LiNi0.33Mn0.33Co0.33O2 and LiFePO4 Electrodes
Authors: Black Serra Ashley , Escudero Carlos , Fehse Marcus , Agostini Giovanni , Fauth Francois , Chatzogiannakis Dimitrios , Ramo-Irrure Alejandro , Reynaud Marine , Casas-Cabanas Montserrat , Palacin Rosa
Published: August 2024

Operando synchrotron radiation-based characterization techniques applied to energy storage materials are becoming a widespread characterization tool as they allow for non-destructive probing of materials with various depth sensitivities through spectroscopy, scattering, and imaging techniques. Moreover, they allow for faster acquisition rates, variable penetration depths, higher spectral or spatial resolution, or access to techniques that are only possible with a continuous tuneable source over a wide photon energy range. Compatibility between the electrochemical cell designs and the experimental setups may force some specific design features and care must be taken to ensure that these do not perturb the electrochemical response of the materials under investigation. The use of operando techniques has intrinsic advantages, as they enable the detection of metastable intermediates, if any, and ensure characterization under real conditions avoiding the risk of ex situ sample evolution during its preparation. However, they do not come with the extent of risks. The interaction between synchrotron radiation and samples, particularly within the intricate milieu of an operational electrochemical cell, can induce unexpected effects in the sample at the measurement spot, thereby jeopardizing the experiment's reliability and biasing data interpretation. While beam-induced effects are well-recognized for their critical impact on characterizing biological samples, macromolecules, or soft matter, they have, until recently, received scant attention within the battery research community, being vaguely referenced and incompletely understood. With the aim of contributing to this ongoing debate, a systematic investigation into these phenomena was carried out conducting a root cause analysis of beam-induced effects during the operando characterization of two commercially employed positive electrode materials: LiNi0.33Mn0.33Co0.33O2 and LiFePO4. The study spans across diverse experimental conditions involving various cell types, absorption and scattering techniques and seeks to correlate beam effects with factors such as radiation energy, photon flux, exposure time, and other parameters associated with radiation dosage. As a conclusion, a set of guidelines and recommendations are provided to evaluate and mitigate beam-induced effects that can affect the outcome of battery operando experiments.
In Situ Soft XAS Study of Electrocatalysts with an Ultrahigh Vacuum-Compatible Liquid Flow Cell
Authors: Kim R. , Li Jialu , Guo Jinghua , Yano Junko
Published: August 2024

Synchrotron X-ray absorption spectroscopy offers a unique tool for investigating the element-specific electronic structure of materials in chemistry and quantum physics fields. In particular, in situ/operando X-ray absorption spectroscopy (XAS) has yielded valuable atomic-level insight into electrocatalysts in operation. While most studies have employed "hard" X-rays that are higher than ~5 keV in energy, "soft" X-rays with energies around or below 1-2 keV have the unique capability to probe core-level excitations of light elements such as oxygen or p→d excitations of 1st-row transition metals. The low-energy soft X-rays easily become absorbed and scattered by ambient air, however, requiring ultrahigh vacuum (UHV) environments. To acquire soft XAS spectra of electrocatalysts in action within a UHV chamber, we employ home-fabricated SiNx membranes and a sealed electrochemical liquid flow cell. We demonstrate the use of our technique with canonical water oxidation catalysts RuO2 and MnOx.
Exploration of Local-Structure and Electrochemical Supercapacitive Performance of Hydrothermally Synthesized α-Fe2O3@Mn3O4@G Composite Electrodes
Authors: Govindarajan Durai , Limphirat Wanwisa , Jayaraman Theerthagiri , Myong Yong Choi , Govindarajan Durai
Published: August 2024

Due to growth in human population and upsurge in the energy needs, researchers have concentrating on the development of novel/advanced electrode materials. Batteries and supercapacitors (SCs) are most significant energy storage technologies present in contemporary gadgets like smartphones, medical equipment’s, electronic devices etc. However, in comparison to SCs, batteries have higher energy densities and lower power. To increase the energy density of SCs, researchers are engaging on developing hybrid SCs based on low-cost metal oxides/carbon based composite electrodes. Herein, we apply a hydrothermal approach to synthesize graphene supported iron and manganese oxide composite for SCs for the first time. The crystalline structure, phase purity, surface morphology, chemical bonding states, elemental composition of the synthesized samples were characterized by XRD, TEM, FE-SEM, XPS and EDS analysis. In addition, XAS (XANES and EXAFS) technique is used to examine the local structure of the composite samples. After confirming all the basic characterizations, the SC electrodes were constructed using synthesized samples, exhibiting a maximum specific capacitance of about 410 F/g at 5 mV/s and 800 F/g at 1 mA/cm2 in an aqueous electrolyte, which is quite higher than that of pristine Fe2O3, pristine Mn3O4, and Fe2O3-Mn3O4 composite electrodes. Furthermore, even after 2,000 cycles, the graphene composite electrode exhibits a capacitance retention of roughly 85% and a coulombic efficiency of nearly 80%. Furthermore, an asymmetric SC device was designed employing graphene composite as the positive electrode and AC as the negative electrode and investigated their performance using CV, GCD, and EIS analyses, These SC device exhibits extraordinary device performance. As a result, the present study provides a new path to fabricate affordable and flexible SC devices for use in real time applications in near future.
(Invited) Probing Electrochemical Interfaces in Catalytic and Energy Materials and Process Using Operando Soft X-Ray Spectroscopy
Authors: Guo Jinghua
Published: August 2024

Advanced energy technology arises from the understanding in fundamental science, thus rest in large on in-situ/operando characterization tools for observing the physical and chemical interfacial processes. Synchrotron based X-ray spectroscopic techniques offers unique characterization in many important energy materials of energy conversion, energy storage and catalysis in regards to the functionality, complexity of material architecture, chemistry and interactions among constituents within. However, it is challenging to reveal the real mechanism of the chemical processes.

In the operando soft X-ray spectroscopy characterization of interfacial phenomena in energy materials and devices, it has been found that the microstructure and composition of materials as well as the microstructure evolution process have a great influence on performances in a variety of fields, e.g., energy conversion and energy storage materials, chemical and catalytic processes. This presentation will show how to best use the in-situ/operando soft X-ray spectroscopy characterization techniques, including soft x-ray absorption spectroscopy (XAS) and resonant inelastic soft X-ray scattering (RIXS) to investigate the real electrochemical mechanism during the operation. The experimental results show how in-situ/operando soft X-ray spectra characterization techniques uncover the phase conversion, chemical and environmental change of elements and other very important information of solid/gas and solid/liquid interfaces in real time, thus further enhance the understanding of real reaction mechanism.
(Invited) Unlocking High-Performance Zero-Cobalt Cathode Active Materials: High-Entropy Doping and Pre-CAM Microstructure Optimization
Authors: Xin Huolin , Jing Yaqi
Published: August 2024

Our recent work, published in Nature (610, 67–73, 2022) and Nature Energy (695–702, 2023), demonstrates the effectiveness of high-entropy doping (HE) in tackling the stability-capacity challenge of zero-cobalt layered cathode active materials (CAMs). While the HE Ni-80% (HE-N80) CAM exhibits competitive discharge capacity, it slightly lags behind NMC-811. This presentation delves into the broader applicability of the HE strategy and highlights the crucial role of pre-CAM microstructure optimization.

Through pre-CAM microstructure optimization, we significantly reduce layered CAMs' anti-site defects, leading to a notable enhancement in discharge capacity. This optimization strategy increases the discharge capacity of the HE-N80 cathode from 210 mAh/g to 220 mAh/g under 0.1C charging and 2.5-4.4V voltage window. Moreover, cycling stability sees a substantial improvement, with a 99.5% capacity retention at 0.5C after 100 cycles. The effectiveness of this methodology extends to CAMs with higher nickel content, as demonstrated by discharge capacities of 225 mAh/g for zero-cobalt HE-N85 and 235 mAh/g for zero-cobalt HE-N90 under the same conditions.

References:

Nature 610, 67–73 (2022).

Nature Energy, 695–702 (2023).
Crystallographic/Morphological Changes and Performance of Lithium Iron Phosphate Deposited By Vacuum Cold Spray
Authors: Rodmyre Collin , Smirnova Alevtina , Kovar Desiderio , Bierschenk Stephen
Published: August 2024

Cold spray offers several advantages for material deposition, including the ability to deposit a wide range of materials without the need for high temperatures, minimizing heat-related distortion and maintaining material properties. Additionally, cold spray is a highly efficient and environmentally friendly process, as it reduces waste and energy consumption compared to traditional thermal spray methods. Lithium iron phosphate (LFP) has been gaining popularity as a cathode material for lithium-ion batteries due to its stable cycling performance, lack of oxygen generation, thermal stability, and use of environmentally friendly iron over nickel or cobalt. In this study, LFP was deposited by vacuum cold spray onto aluminum foil substrate to investigate the viability of cold spray as a possible method of manufacturing all-solid-state batteries. Results were obtained through in-situ X-ray diffraction (XRD), scanning electron microscopy (SEM), and in-situ transmission electron microscopy (TEM). Electrochemical results were obtained by assembling cold spray deposited LFP into half-cells with Li-metal anode and liquid electrolyte before being tested on electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and C-Rate. Due to the high impact velocities during cold spray, crystalline LFP was observed to undergo changes to an amorphous phase. Using in-situ X-ray diffraction (XRD), scanning electron microscopy (SEM), and in-situ transmission electron microscopy (TEM) the crystallographic and morphological changes to cold spray deposited LFP were investigated across various temperatures. In-situ XRD initially showed a decrease in crystallinity with crystallinity being restored with elevated temperatures, with in-situ TEM further supporting these findings. Investigation with SEM showed LFP particles undergo deformation upon impact with a mix of intact particles interspersed throughout to create a dense layer. Electrochemical impedance spectroscopy (EIS) of assembled half-cells show low resistance of 90Ω with further reduction to 60Ω upon cycling of the cell. In terms of cycling performance, initial discharge capacities showed 80 mAh/g and 20mAh/g at 0.1C and 1C respectively. These capacities dropped further with repeated cycling. Future work will be focused on improving capacity, annealing post deposition to restore crystallinity, and incorporation of solid electrolyte.
Scalable One-Pot Synthesis of Nanostructured P2-Type Na2/3Ni1/3Mn2/3O2 Cathode Material for High-Performance Na-Ion Batteries
Authors: Hassan Mohamed H. , Bruzzi Chiara , Detsi Eric
Published: August 2024

Sodium-ion batteries (SIBs) based on sodium transition metal oxides are considered as a viable alternative to lithium-ion batteries (LIBs) for grid-scale energy storage. This is because the critical elements used in these SIBs, such as sodium, manganese, and nickel, are abundantly available, and their supply chain does not pose any geopolitical risk like lithium and cobalt used in common LIB cathodes.1 Among sodium transition metal oxide cathodes, the P2-type Na2/3[Ni1/3Mn2/3]O2 (NNMO) is a promising material due to its high operating voltage (up to 4.5 V vs Na/Na+) and high capacity. When cycled between 2-4.5 V vs Na/Na+, it has a capacity of 173 mAh/g.2 This combination of high operating voltage and high capacity allows NNMO to outperform common LIBs in terms of energy density. Therefore, SIBs based on NNMO cathode are a scalable alternative to LIBs.

Unfortunately, the current method used to produce NNMO through solid-state conversion is a time and energy-intensive process. It requires a temperature above 800 degrees Celsius and takes at least 12 hours to make a single batch of NNMO. Moreover, NNMO formed using this method has large particle sizes of a few micrometers. In my presentation, I will introduce a new and highly scalable method for synthesizing NNMO. This method can create NNMO in less than 20 minutes, which is much faster than the usual 12+ hours required by existing methods. Additionally, our protocol produces Nano-NNMO particles with size in the sub-200 nm. Nanoscale NNMO is crucial because it enhances the electrochemical performance of the materials, which I will also discuss.

Key words: Sodium-ion batteries, Na2/3[Ni1/3Mn2/3]O2, high capacity, nanoparticles, rapid synthesis.

References

(1) Wang, C.; Liu, L.; Zhao, S.; Liu, Y.; Yang, Y.; Yu, H.; Lee, S.; Lee, G.-H.; Kang, Y.-M.; Liu, R.; et al. Tuning local chemistry of P2 layered-oxide cathode for high energy and long cycles of sodium-ion battery. Nature Communications
2021, 12 (1), 2256. DOI: 10.1038/s41467-021-22523-3.

(2) Zhang, J.; Wang, W.; Wang, W.; Wang, S.; Li, B. Comprehensive Review of P2-Type Na2/3Ni1/3Mn2/3O2, a Potential Cathode for Practical Application of Na-Ion Batteries. ACS Applied Materials & Interfaces
2019, 11 (25), 22051-22066. DOI: 10.1021/acsami.9b03937.
Prelithiated Silicon Anodes for High-Energy and High-Power Lithium-Ion Batteries
Authors: Elangovan Ayyappan , Hays Kevin A. , Kumar Sujeet , Lopez Herman A.
Published: August 2024

Lithium-ion batteries (LIBs) are pivotal in powering modern electronic devices and next-generation land and air electric vehicles. Silicon-based anodes are considered the next technology to replace traditional graphite anodes due to their high theoretical capacity. However, the inherent challenges associated with their large volume expansion and high irreversible capacity loss (IRCL) limit their practical application. This abstract explores our patented strategy of prelithiation as a viable approach to mitigate the IRCL limitations of SiOx dominant anodes. Prelithiation involves the precise addition of supplemental lithium into the anode, mitigating the adverse effects of initial lithiation and enhancing overall cyclability, energy, power, and extreme fast charge capability for silicon oxide dominant LIBs. Various prelithiation techniques, including Li powder, Li slurry, Li-foil, and the chemical doping of SiOx are examined to evaluate their effectiveness in providing supplemental lithium. The effectiveness of the prelithiation process is assessed by examining the impact on the structural stability, cycling performance, power capability, and rate capability of SiOx dominant anodes integrated into high-capacity (~30 Ah) pouch cells. Our focus is to emphasize prelithiation as a practical and scalable solution to enhance the electrochemical performance of SiOx dominant anodes, contributing to the development of high-energy and high-power LIBs enabling advanced air mobility and high-performance electric vehicles. The findings presented in this abstract contribute to the growing body of knowledge aimed at advancing the fundamental understanding and practical implementation of prelithiation as an enabler for SiOx-based anodes in LIBs.

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(Invited) Towards Scalable and Low-Cost Direct Recycling of Lithium-Ion Batteries
Authors: Chen Zheng
Published: August 2024

The increasing amount of lithium-ion battery (LIBs) consumption will result in the resource shortage and price increase of lithium and precious transition metals that are critical for making high-performance LIBs. Also, future batteries that mainly use low-cost materials (Na, Fe, Mn) will have limited economic benefits to recycle even though the wastes generated from disposal of used batteries can cause severe environment pollution. In this context, design of low-cost and scalable recycling and regeneration process for spent batteries is attracting growing interest. This talk will focus on our recent progress on direct recycling and regeneration spent LIBs, which can lead to new electrode materials that can show the same level of performance as the native materials. We will show successful recycling of various battery materials, including cathode (LiMO2, LiMn2O4, and LiFePO4) and anode (graphite) using the direct regeneration approach. We will discuss how we integrate different operation steps into a pathway for scalable directly recycling.
Dewetted Nanoparticles – a Platform to Study Nanoscale Effects in Electrocatalysis
Authors: Altomare Marco
Published: August 2024

To obtain interpretable electrochemical responses and define design criteria for electrocatalysts with enhanced performance, it is crucial to minimize the chemical and material complexity of electrodes [1]. Wet chemical methods are often applied in research to produce high surface area electrocatalysts, typically in the form of inks and coatings, including additives, binders, ionomers, etc., hence featuring complex, often unknown, structure, morphology, and chemical composition. This complexity might also lead to undesired mass transfer limitations and make it difficult to assess intrinsic catalytic properties of electrocatalysts.

This contribution is on designing and nanostructuring binder- and ionomer-free electrodes by solid-state dewetting [2,3], i.e., the heat-induced agglomeration of sputtered thin metal films into nanoparticles (NPs) with tunable loading, size, structure, and composition.

In this context, I discuss the following aspects: i) How dewetting can be steered to produce model, spatially separated and coherently oriented metal NPs with defined exposed facets [4]; ii) The use of dewetted electrodes to study nanoscale effects such as electronic metal support interactions (EMSI) in electrocatalytic reactions [5]; and iii) possibilities to apply scanning electrochemical techniques, in-situ spectroscopic tools or single-particle probes to investigate surface and interfacial phenomena of dewetted NP electrocatalysts.

[1] A.R. Akbashev, ACS Catal. 2022, 12, 8, 4296.

[2] C.V. Thompson, Annu. Rev. Mater. Res. 2012, 42, 399.

[3] Altomare et al., Chem. Sci. 2016, 7, 6865.

[4] Sharma et al., ECS 2023 https://ecs.confex.com/ecs/244/meetingapp.cgi/Paper/180073

[5] Harsha et al., ECS 2023 https://ecs.confex.com/ecs/244/meetingapp.cgi/Paper/179874
Cryogenic Atom Probe Tomograph to Resolve Confined Electrochemical Interfaces
Authors: Waszkiewicz Oliver Richard , El-Zoka Ayman A. , Ryan Mary P.
Published: August 2024

Atom Probe Tomography (APT) is an analysis technique capable of providing a 3-dimensional, element-sensitive map of needle-shaped samples (where the tip radius is about 50 nm) with sub-nanometre resolution [1]. APT analysis is carried out at temperatures in the range of 25-75 K to limit the thermal motion of surface atoms which improves the spatial and mass resolution. As a result, this enables the analysis of frozen liquids, and by extension solid-liquid interfaces, by so-called “cryo-APT”. While this was historically challenging, recent advancements in UHV-cryogenic transfer and sample preparation methods now make it possible for the atomic scale analysis of interfacial species in electrochemical systems [2-4].

In this study, we will attempt to explore the effect of nanoscale geometrical confinement on the distribution of interfacial ions for the first time and to resolve the electric double layer, using cryo-APT. We will describe the workflow for cryo-APT sample preparation to study confined solid-liquid interfaces, using nanoporous gold as a template material with a frozen sodium iodide solution inside its pores. APT reconstructions will allow 3-dimensional mapping of aqueous interfacial species, helping to develop our understanding of the structure of the electric double layer under nanoscale geometrical confinement. The attached Figure shows an SEM image of the later stages of cryo-FIB milling of an APT tip of frozen deionised water and 50 mM sodium iodide and a segment of the related APT atom map reconstruction.

References

[1] Erwin W. Müller, John A. Panitz, and S. Brooks McLane. “The Atom-Probe Field Ion Mi-

croscope”. In: Review of Scientific Instruments 39.1 (1968), pp. 83–86. issn: 0034-6748.

[2] A. A. El-Zoka et al. “Enabling near-atomic–scale analysis of frozen water”. In: Science Advances

6.49 (Dec. 4, 2020). Publisher: American Association for the Advancement of Science, eabd6324.

[3] T. M. Schwarz et al. “Field evaporation and atom probe tomography of pure water tips”.

In: Scientific Reports 10.1 (Nov. 20, 2020). Number: 1 Publisher: Nature Publishing Group,

p. 20271. issn: 2045-2322.

[4] Stephenson LT, Szczepaniak A, Mouton I, Rusitzka KAK, Breen AJ, Tezins U, et al. (2018) The Laplace Project: An integrated suite for preparing and transferring atom probe samples under cryogenic and UHV conditions. PLoS ONE 13(12): e0209211.

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Magnetic Field Driven Dynamic Reorganization of Electrocatalytic Interface for Sustainable Enhancement in Oxygen Evolution
Authors: Saha Jayeeta
Published: August 2024

Hydrogen with high calorific content (150 MJ/kg) and environment-friendly combustion product (H2O) becomes the alternative fossil fuel. Catalytic electrolysis of water is one of the attractive routes for generating H2. Energy-efficient and cost-effective electrolytic production of H2 has predominantly focused on lowering the overpotential for water splitting process by developing newer non-Pt group-based catalysts.

This work demonstrates a new direction towards sustainable oxygen evolution reaction (OER) by exploiting the fundamental interplay of electromagnetic forces. Introducing an external magnetic field (Hext = 100 mT) perpendicular to the heterogeneous electrocatalytic interface produces an unprecedented increase in rate of electrocatalytic OER in phosphate buffer with pH=7. Such
electromagnetic

catalysis
is achieved with metal phosphides (NiCoP and NiCoFeP) with different morphology, leading 2.5 fold increase in the OER current density and concomitant lowering of overpotential by 10% (Hext = 100 mT). Thereby, 50% lowering of charge transfer resistance (Rct) is achieved. This is substantiated by the lowering of the Tafel slope (by 5%) in the presence of Hext. Thus, we report two important observations influenced by the magnetic field: (a) direct effect of magnetic field on the catalyst surface to reduce the charge-transfer resistance, (b) spin-dependant OER process to get influenced under magnetic field and (c) indirect effect of magnetic field to sustain the magneto-electrocatalytic enhancement even after removing the magnetic field. The time-scale of magnetic relaxation is million times higher than conventional spin-lattice relaxation events in para/ferromagnetic systems. Such long-term stability of magnetized states is predominantly proposed to be originating from the NiCoP and NiCoFeP interface. So, we attribute the long-lived states to be additionally contributed from the volumetric expansion and active site expansion of the catalyst upon magnetization. Catalyst interface is arising due to the dendritic structure of catalyst. Such synergism of magnetization, is expected to increase the applicability of magneto-electrocatalysis as a more sustainable electrocatalytic approach towards a hydrogen-driven economy.

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An AC and DC Electric Field Effect Based Charged Particle Focusing Scheme for Particle Beam Mass Spectrometer
Authors: Yoon Jong-Min , Lee Seungjae , Park Kihong , Kim Taesung
Published: August 2024

Particle Beam Mass Spectrometer (PBMS) is a mass analyzer based particle sizer, features a few to hundreds of nanometer (nm) sizing capabilities in environmental pressures above hundreds of mTorr. The above feature makes the PBMS be used as in-situ process monitoring schemes for several kinds of semiconductor process equipment (e.g. Chemical Vapor Deposition). However, it still cannot be used in other process equipment (e.g. Plasma etching, Ion implantation) which requires lower process pressure conditions than the PBMS operation limits. The bottleneck of pressure limits comes from an aerodynamic lens component, which focuses incoming particles in background gas using repetitive fluidic contraction and expansion effects. These effects hard to be happened when the target particles are surrounded in molecular or transition background gas regions. In order to lower the operating pressure limits, other focusing schemes are required.

In this study, an alternative particle focusing scheme which uses AC and DC electric field effects is proposed. The proposed scheme uses a stacked-ring ion funnel structure with variable AC and DC electric sources, for driving AC and DC potential variations along the funnel’s axial direction. While radial electric potential wells produced by AC frequency components induce particles’ radial position concentration to the funnel axis center, potential well depth and axial well depth steepness is controlled by AC amplitudes and DC source values.

Simulation results show that with the proposed scheme, more than 50% of particle transmission efficiencies are obtained for 5 nm – 100 nm sized charged particles moving with Maxwellian velocities in molecular background region. The results come from AC electric sources with 200 Hz - 20 kHz frequency ranges and within 50 V amplitude ranges, and DC electric sources within 50 V ranges which are feasible values for hardware implementation.