We present a novel, and computationally cheap, way to estimate electrostatic screening lengths from simulations of Restricted Primitive Model (RPM) electrolytes. We demonstrate that the method is accurate by comparisons with simulated long-ranged parts of the charge density, at various Bjerrum lengths, salt concentrations and ion diameters. We find substantial underscreening in low dielectric solvent, but with an ``aqueous'' solvent, there is instead overscreening, the degree of which increases with ion size. Our method also offers a possible path to (future) more accurate classical density functional treatments of ionic fluids.
{"title":"An efficient method to establish electrostatic screening lengths of Restricted Primitive Model electrolytes","authors":"Jan Forsman, David Ribar, Clifford Edwin Woodward","doi":"10.1039/d4cp00546e","DOIUrl":"https://doi.org/10.1039/d4cp00546e","url":null,"abstract":"We present a novel, and computationally cheap, way to estimate electrostatic screening lengths from simulations of Restricted Primitive Model (RPM) electrolytes. We demonstrate that the method is accurate by comparisons with simulated long-ranged parts of the charge density, at various Bjerrum lengths, salt concentrations and ion diameters. We find substantial underscreening in low dielectric solvent, but with an ``aqueous'' solvent, there is instead overscreening, the degree of which increases with ion size. Our method also offers a possible path to (future) more accurate classical density functional treatments of ionic fluids.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141496053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simon Bacon, Shumaila Babar, Matthew Dent, Allan Foster, Joseph Paul Baboo, Teng Zhang, John F Watts, Constantina Lekakou
The present investigation fits the reaction kinetics of a lithium-sulfur (Li-S) battery with polar electrolyte employing a novel two-phase continuum multipore model. The continuum two-phase model considers processes in both the liquid electrolyte phase and the solid precipitates phase, where the diffusion coefficients of the Li+ ions in a solvent-softened solid state are determined from molecular dynamics simulations. Solubility experiments yield the saturation concentration of sulfur and lithium sulfides in the polar electrolyte employed in this study. The model describes the transport of dissolved molecular and ion species in pores of different size in solvated or desolvated form, depending on pore size. The Li-S reaction model in this study is validated for electrolyte 1 M LiPF6 in EC/DMC. It includes seven redox reactions and two cyclic non-electrochemical reactions in the cathode, and the lithium redox reaction at the anode. Electrochemical reactions are assumed to take place in the electrolyte solution or the solid state and cyclic reactions are assumed to take place in the liquid electrolyte phase only. The determination of the reaction kinetics parameters takes place via fitting the model predictions with experimental data of a cyclic voltammetry cycle with in operando UV-vis spectroscopy.
本研究采用新型两相连续多孔模型拟合了极性电解质锂硫（Li-S）电池的反应动力学。连续两相模型考虑了液态电解质相和固态沉淀相的过程，其中锂+ 离子在溶剂软化固态中的扩散系数是通过分子动力学模拟确定的。溶解度实验得出了本研究采用的极性电解质中硫和硫化锂的饱和浓度。该模型描述了溶解的分子和离子物种在不同大小的孔隙中以溶解或去溶解的形式（取决于孔隙大小）进行的传输。本研究中的锂-S 反应模型针对 EC/DMC 中的 1 M LiPF6 电解质进行了验证。它包括阴极的七个氧化还原反应和两个循环非电化学反应，以及阳极的锂氧化还原反应。电化学反应假定发生在电解质溶液或固态中，循环反应假定只发生在液态电解质阶段。反应动力学参数的确定是通过将模型预测与循环伏安法周期的实验数据进行拟合，并结合操作中的紫外-可见光谱来实现的。
{"title":"Reaction kinetics of lithium-sulfur batteries with a polar Li-ion electrolyte: modeling of liquid phase and solid phase processes.","authors":"Simon Bacon, Shumaila Babar, Matthew Dent, Allan Foster, Joseph Paul Baboo, Teng Zhang, John F Watts, Constantina Lekakou","doi":"10.1039/d4cp02061h","DOIUrl":"https://doi.org/10.1039/d4cp02061h","url":null,"abstract":"<p><p>The present investigation fits the reaction kinetics of a lithium-sulfur (Li-S) battery with polar electrolyte employing a novel two-phase continuum multipore model. The continuum two-phase model considers processes in both the liquid electrolyte phase and the solid precipitates phase, where the diffusion coefficients of the Li<sup>+</sup> ions in a solvent-softened solid state are determined from molecular dynamics simulations. Solubility experiments yield the saturation concentration of sulfur and lithium sulfides in the polar electrolyte employed in this study. The model describes the transport of dissolved molecular and ion species in pores of different size in solvated or desolvated form, depending on pore size. The Li-S reaction model in this study is validated for electrolyte 1 M LiPF<sub>6</sub> in EC/DMC. It includes seven redox reactions and two cyclic non-electrochemical reactions in the cathode, and the lithium redox reaction at the anode. Electrochemical reactions are assumed to take place in the electrolyte solution or the solid state and cyclic reactions are assumed to take place in the liquid electrolyte phase only. The determination of the reaction kinetics parameters takes place <i>via</i> fitting the model predictions with experimental data of a cyclic voltammetry cycle with <i>in operando</i> UV-vis spectroscopy.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141490049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The photoionization (PI) spectra of small gas-phase yttrium monoxide clusters, YnO (n = 1–8), are investigated, and the adiabatic ionization energies are determined. The stable structures are obtained from the density functional theory (DFT) calculations. The ground state structures are further confirmed by CCSD(T) method. The PI spectra are calculated for these stable structures and are compared with the experimental PI spectra. The ground-state structures of the neutral and cation clusters are experimentally assigned with confidence on the basis of a favourable agreement between the experimental and calculated PI spectra. New structures are proposed for Y2O, Y6O, and Y8O compared to the previous literature. Y2O is a linear molecule in the ground state that was previously proposed as a C2v bend molecule. The YnO clusters become 3-dimensional from n ≥ 3. The O atom stays outside, bridging a triangular face of yttrium clusters. Chemical bonding between the yttrium and oxygen atoms is mostly ionic. The excess charge on the oxygen atom is around 1.4e–, transferred from the yttrium atoms bonded with it. Yttrium atoms are mostly covalently bonded. However, for the bigger clusters, free charges of both polarities appear on yttrium atoms that are not bonded with oxygen, indicating ionic interactions. Frontier orbitals consist of mainly delocalized 4d electrons with some 5s contributions, forming Y–Y bonding interactions, but with little contribution and zero contribution from the oxygen orbitals, regardless of the cluster size. The lost electron of the YnO+ mostly comes from 5s orbitals of all Y atoms in the cluster up to size n = 4, and then from 4d–5s hybrid orbitals from n ≥ 5, with d contribution increasing with size. This is contrary to the previous view in the literature that photoionization occurs from a localized 4d orbital.
研究了小型气相一氧化钇团簇 YnO（n = 1-8）的光离子化（PI）光谱，并确定了绝热电离能。通过密度泛函理论（DFT）计算得到了稳定的结构。基态结构通过 CCSD(T) 方法得到进一步证实。计算了这些稳定结构的 PI 光谱，并与实验 PI 光谱进行了比较。根据实验和计算的 PI 光谱之间的良好一致性，实验确定了中性和阳离子簇的基态结构。与以前的文献相比，提出了 Y2O、Y6O 和 Y8O 的新结构。Y2O 在基态是一个线性分子，以前曾被认为是一个 C2v 弯曲分子。从 n ≥ 3 开始，YnO 簇变成三维的。O 原子留在外面，在钇簇的三角形面上架桥。钇原子和氧原子之间的化学键主要是离子键。氧原子上的多余电荷约为 1.4e-，是从与其结合的钇原子转移过来的。钇原子大多以共价键结合。然而，对于较大的簇，未与氧键合的钇原子上出现了两种极性的自由电荷，表明存在离子相互作用。前沿轨道主要由分散的 4d 电子和一些 5s 电子组成，形成 Y-Y 键相互作用，但无论簇的大小如何，氧轨道的贡献都很小，甚至为零。YnO+ 失去的电子在 n = 4 尺寸之前大多来自于簇中所有 Y 原子的 5s 轨道，从 n ≥ 5 开始则来自于 4d-5s 混合轨道，d 贡献随尺寸增大而增加。这与以往文献中认为光离子化发生于局部 4d 轨道的观点相反。
{"title":"Structure of Small Yttrium Monoxide Clusters, Chemical Bonding, and Photoionization: Threshold Photoionization and Density Functional Theory Investigations","authors":"Varun Vinayak Deshpande, Vaibhav Chauhan, Debashis Bandyopadhyay, Anakuthil Anoop, Soumen Bhattacharyya","doi":"10.1039/d4cp02351j","DOIUrl":"https://doi.org/10.1039/d4cp02351j","url":null,"abstract":"The photoionization (PI) spectra of small gas-phase yttrium monoxide clusters, Y<small><sub>n</sub></small>O (n = 1–8), are investigated, and the adiabatic ionization energies are determined. The stable structures are obtained from the density functional theory (DFT) calculations. The ground state structures are further confirmed by CCSD(T) method. The PI spectra are calculated for these stable structures and are compared with the experimental PI spectra. The ground-state structures of the neutral and cation clusters are experimentally assigned with confidence on the basis of a favourable agreement between the experimental and calculated PI spectra. New structures are proposed for Y<small><sub>2</sub></small>O, Y<small><sub>6</sub></small>O, and Y<small><sub>8</sub></small>O compared to the previous literature. Y<small><sub>2</sub></small>O is a linear molecule in the ground state that was previously proposed as a C<small><sub>2v</sub></small> bend molecule. The Y<small><sub>n</sub></small>O clusters become 3-dimensional from n ≥ 3. The O atom stays outside, bridging a triangular face of yttrium clusters. Chemical bonding between the yttrium and oxygen atoms is mostly ionic. The excess charge on the oxygen atom is around 1.4e<small><sup>–</sup></small>, transferred from the yttrium atoms bonded with it. Yttrium atoms are mostly covalently bonded. However, for the bigger clusters, free charges of both polarities appear on yttrium atoms that are not bonded with oxygen, indicating ionic interactions. Frontier orbitals consist of mainly delocalized 4d electrons with some 5s contributions, forming Y–Y bonding interactions, but with little contribution and zero contribution from the oxygen orbitals, regardless of the cluster size. The lost electron of the Y<small><sub>n</sub></small>O<small><sup>+</sup></small> mostly comes from 5s orbitals of all Y atoms in the cluster up to size n = 4, and then from 4d–5s hybrid orbitals from n ≥ 5, with d contribution increasing with size. This is contrary to the previous view in the literature that photoionization occurs from a localized 4d orbital.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yingnan Liu, Dashuai Wang, Bin Yang, Zhongjian Li, Tao Zhang, Raul D. Rodriguez, Lecheng Lei, Yang Hou
In carbon dioxide electrochemical reduction (CO2ER), due to isolated catalysts encounter challenges in meeting the demands of intricate processes for producing multi-carbon (C2+) products, tandem catalysis is emerging as a promising approach. Nevertheless, there remains an insufficient theoretical understanding of designing tandem catalysts. Herein, we utilized density functional theory (DFT) to screen 80 tandem catalysts for efficient CO2ER to C2 products systematically, which combines the advantages of nitrogen-doped carbon-supported transition metal single-atom catalysts (M-N-C) and copper clusters. Three crucial criteria were designed to select structures for generation and transfer of *CO, and facilitating C-C coupling. The optimal Cu/RuN4-pl catalyst exhibited an excellent ethanol production capacity. Additionally, the relationship between CO adsorption strength and transfer energy barrier was established, and the influence of electronic structure on its adsorption strength was studied. It provided a novel and well-considered solution and theoretical guidance for the design of rational composition and structurally superior tandem catalysts.
{"title":"Mechanistic insights into high-throughput screening of tandem catalysts for CO2 reduction to multi-carbon products","authors":"Yingnan Liu, Dashuai Wang, Bin Yang, Zhongjian Li, Tao Zhang, Raul D. Rodriguez, Lecheng Lei, Yang Hou","doi":"10.1039/d4cp01622j","DOIUrl":"https://doi.org/10.1039/d4cp01622j","url":null,"abstract":"In carbon dioxide electrochemical reduction (CO2ER), due to isolated catalysts encounter challenges in meeting the demands of intricate processes for producing multi-carbon (C2+) products, tandem catalysis is emerging as a promising approach. Nevertheless, there remains an insufficient theoretical understanding of designing tandem catalysts. Herein, we utilized density functional theory (DFT) to screen 80 tandem catalysts for efficient CO2ER to C2 products systematically, which combines the advantages of nitrogen-doped carbon-supported transition metal single-atom catalysts (M-N-C) and copper clusters. Three crucial criteria were designed to select structures for generation and transfer of *CO, and facilitating C-C coupling. The optimal Cu/RuN4-pl catalyst exhibited an excellent ethanol production capacity. Additionally, the relationship between CO adsorption strength and transfer energy barrier was established, and the influence of electronic structure on its adsorption strength was studied. It provided a novel and well-considered solution and theoretical guidance for the design of rational composition and structurally superior tandem catalysts.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141496019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taotao Gao, Qi An, Xiangmin Tang, Qu Yue, Yang Zhang, Bing Li, Panpan Li, Zhaoyu Jin
Hydrogen energy with the advantages of high calorific value, renewable nature, and zero carbon emissions is considered an ideal candidate for clean energy in the future. The electrochemical decomposition of water, powered by renewable and clean energy sources, presents a sustainable and environmentally friendly approach to hydrogen production. However, the traditional electrochemical overall water-splitting reaction (OWSR) is limited by the anodic oxygen evolution reaction (OER) with sluggish kinetics and high energy consumption. Besides, the generation of reactive oxygen species at high oxidation potentials can lead to equipment degradation and increase maintenance costs. To address these challenges, a series of innovative hydrogen production systems have been developed. These systems involve coupling the cathodic hydrogen evolution reaction (HER) with thermodynamically favorable anodic oxidation reactions that have lower oxidation potentials, or adjusting the pH gradient of the electrolytes. In this review, we aim to provide an overview of the advancements in electrochemical hydrogen production strategies with low energy consumption, including (1) traditional electrochemical overall water splitting reaction (OWSR, HER-OER); (2) The small molecule sacrificial agent oxidation reaction (SAOR) and (3) the electrochemical oxidation synthesis reaction (EOSR) coupling with the HER (HER-SAOR, HER-EOSR), respectively; (4) Regulating the pH gradient of the cathodic and anodic electrolytes. The operating principle, advantages, and the latest progress of these hydrogen production systems are analyzed in detail. Furthermore, we also provide a perspective on the potential challenges and future directions to foster further advancements in electrocatalytic green sustainable hydrogen production.
{"title":"Recent Progress in Energy-Saving Electrocatalytic Hydrogen Production via Regulating Anodic Oxidation Reaction","authors":"Taotao Gao, Qi An, Xiangmin Tang, Qu Yue, Yang Zhang, Bing Li, Panpan Li, Zhaoyu Jin","doi":"10.1039/d4cp01680g","DOIUrl":"https://doi.org/10.1039/d4cp01680g","url":null,"abstract":"Hydrogen energy with the advantages of high calorific value, renewable nature, and zero carbon emissions is considered an ideal candidate for clean energy in the future. The electrochemical decomposition of water, powered by renewable and clean energy sources, presents a sustainable and environmentally friendly approach to hydrogen production. However, the traditional electrochemical overall water-splitting reaction (OWSR) is limited by the anodic oxygen evolution reaction (OER) with sluggish kinetics and high energy consumption. Besides, the generation of reactive oxygen species at high oxidation potentials can lead to equipment degradation and increase maintenance costs. To address these challenges, a series of innovative hydrogen production systems have been developed. These systems involve coupling the cathodic hydrogen evolution reaction (HER) with thermodynamically favorable anodic oxidation reactions that have lower oxidation potentials, or adjusting the pH gradient of the electrolytes. In this review, we aim to provide an overview of the advancements in electrochemical hydrogen production strategies with low energy consumption, including (1) traditional electrochemical overall water splitting reaction (OWSR, HER-OER); (2) The small molecule sacrificial agent oxidation reaction (SAOR) and (3) the electrochemical oxidation synthesis reaction (EOSR) coupling with the HER (HER-SAOR, HER-EOSR), respectively; (4) Regulating the pH gradient of the cathodic and anodic electrolytes. The operating principle, advantages, and the latest progress of these hydrogen production systems are analyzed in detail. Furthermore, we also provide a perspective on the potential challenges and future directions to foster further advancements in electrocatalytic green sustainable hydrogen production.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maho Tanaka, Rai Kobayashi, Yasuyuki Tsuboi, Ken-ichi Yuyama
Confining molecules and ions at a specific position in a solution enables the control of chemical reactions and analysis of tiny amounts of substances. Here, we demonstrate local condensation of a temperature responsive ionic liquid using optical tweezers. Two kinds of microdroplets are prepared through phase separation or nanocluster formation under the irradiation of a near-infrared laser beam. The droplet formation mechanism is discussed in view of the evolution of an optical potential well and the local temperature distribution.
{"title":"Optical trapping of nanoclusters formed in a temperature-responsive ionic liquid aqueous solution under focused near-infrared laser irradiation","authors":"Maho Tanaka, Rai Kobayashi, Yasuyuki Tsuboi, Ken-ichi Yuyama","doi":"10.1039/d4cp02363c","DOIUrl":"https://doi.org/10.1039/d4cp02363c","url":null,"abstract":"Confining molecules and ions at a specific position in a solution enables the control of chemical reactions and analysis of tiny amounts of substances. Here, we demonstrate local condensation of a temperature responsive ionic liquid using optical tweezers. Two kinds of microdroplets are prepared through phase separation or nanocluster formation under the irradiation of a near-infrared laser beam. The droplet formation mechanism is discussed in view of the evolution of an optical potential well and the local temperature distribution.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adam Mizera, Sylwia Zięba, Michał Bielejewski, Alina T Dubis, Andrzej Łapiński
The charge carriers in conducting pyrrole-co-poly(pyrrole-3-carboxylic) were examined using high-pressure Raman spectroscopy. The molecular structure of the new copolymer was investigated using high-resolution 13C ssNMR, 1H-13C 2D NMR correlation spectroscopy, and density functional theory (DFT) calculations. Bands in Raman spectra that showed the presence of polarons and bipolarons were studied. It was observed that the quantity of polarons and bipolarons correlated with the hydrostatic pressure. At a pressure of 4 GPa, an anomaly in the correlation between pressure and the position of the Raman band was identified.
{"title":"Effect of hydrostatic pressure on charge carriers in a conducting pyrrole-<i>co</i>-poly(pyrrole-3-carboxylic) copolymer.","authors":"Adam Mizera, Sylwia Zięba, Michał Bielejewski, Alina T Dubis, Andrzej Łapiński","doi":"10.1039/d4cp01087f","DOIUrl":"https://doi.org/10.1039/d4cp01087f","url":null,"abstract":"<p><p>The charge carriers in conducting pyrrole-<i>co</i>-poly(pyrrole-3-carboxylic) were examined using high-pressure Raman spectroscopy. The molecular structure of the new copolymer was investigated using high-resolution <sup>13</sup>C ssNMR, <sup>1</sup>H-<sup>13</sup>C 2D NMR correlation spectroscopy, and density functional theory (DFT) calculations. Bands in Raman spectra that showed the presence of polarons and bipolarons were studied. It was observed that the quantity of polarons and bipolarons correlated with the hydrostatic pressure. At a pressure of 4 GPa, an anomaly in the correlation between pressure and the position of the Raman band was identified.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141475480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Moritz Hirsbrunner, Anastasiia Mikheenkova, Pontus Törnblom, Robert House, Wenliang Zhang, Tegun Citra Asmara, Yuan Wei, Thorsten Schmitt, Hakan Rensmo, Soham Mukherjee, Maria Hahlin, Laurent Duda
Vibrationally-resolved resonant inelastic X-ray scattering (VR-RIXS) at the O K-edge is emerging as a powerful tool for identifying embedded molecules in lithium-ion battery cathodes. Here, we investigate two known oxygen redox-active cathode materials: the commercial LixNi0.90Co0.05Al0.05O2 (NCA) used in electric vehicles and the high-capacity cathode material Li1.2Ni0.13Co0.13Mn0.54O2 (LRNMC) for next-generation Li-ion batteries. We report the detection of a novel vibrational RIXS signature for Li-ion battery cathodes appearing in the O K pre-peak above 533 eV that we attribute to OH-groups. We discuss likely locations and pathways for OH-group formation and accumulation throughout the active cathode material. Initial-cycle behaviour for LRNMC shows that OH-signal strength correlates with the cathodes state of charge, though reversibility is incomplete. The OH-group RIXS signal strength in long-term cycled NCA is retained. Thus, VR-RIXS offers a path for gaining new insights to oxygen reactions in battery materials.
O K 边的振动分辨共振非弹性 X 射线散射 (VR-RIXS) 正在成为识别锂离子电池正极中嵌入分子的有力工具。在这里，我们研究了两种已知的氧氧化还原活性正极材料：用于电动汽车的商用 LixNi0.90Co0.05Al0.05O2 (NCA)，以及用于下一代锂离子电池的高容量正极材料 Li1.2Ni0.13Co0.13Mn0.54O2 (LRNMC)。我们报告了对锂离子电池阴极的新型振动 RIXS 特征的检测，该特征出现在 533 eV 以上的 O K 前峰，我们将其归因于 OH 基团。我们讨论了在整个活性阴极材料中形成和积累 OH 基团的可能位置和途径。LRNMC 的初始循环行为表明，OH 信号强度与阴极的电荷状态相关，尽管可逆性不完全。长期循环 NCA 中的 OH 组 RIXS 信号强度保持不变。因此，VR-RIXS 为深入了解电池材料中的氧反应提供了一条途径。
{"title":"Vibrationally-resolved RIXS reveals OH-group formation in oxygen redox active Li-ion battery cathodes","authors":"Moritz Hirsbrunner, Anastasiia Mikheenkova, Pontus Törnblom, Robert House, Wenliang Zhang, Tegun Citra Asmara, Yuan Wei, Thorsten Schmitt, Hakan Rensmo, Soham Mukherjee, Maria Hahlin, Laurent Duda","doi":"10.1039/d4cp01766h","DOIUrl":"https://doi.org/10.1039/d4cp01766h","url":null,"abstract":"Vibrationally-resolved resonant inelastic X-ray scattering (VR-RIXS) at the O <em>K</em>-edge is emerging as a powerful tool for identifying embedded molecules in lithium-ion battery cathodes. Here, we investigate two known oxygen redox-active cathode materials: the commercial Li<small><sub>x</sub></small>Ni<small><sub>0.90</sub></small>Co<small><sub>0.05</sub></small>Al<small><sub>0.05</sub></small>O<small><sub>2</sub></small> (NCA) used in electric vehicles and the high-capacity cathode material Li<small><sub>1.2</sub></small>Ni<small><sub>0.13</sub></small>Co<small><sub>0.13</sub></small>Mn<small><sub>0.54</sub></small>O<small><sub>2</sub></small> (LRNMC) for next-generation Li-ion batteries. We report the detection of a novel vibrational RIXS signature for Li-ion battery cathodes appearing in the O <em>K</em> pre-peak above 533 eV that we attribute to OH-groups. We discuss likely locations and pathways for OH-group formation and accumulation throughout the active cathode material. Initial-cycle behaviour for LRNMC shows that OH-signal strength correlates with the cathodes state of charge, though reversibility is incomplete. The OH-group RIXS signal strength in long-term cycled NCA is retained. Thus, VR-RIXS offers a path for gaining new insights to oxygen reactions in battery materials.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Performing the PBE+G0W0+BSE calculations, structural, electronic, and optical properties of functionalized hexagonal boron nitride (h-BN) bilayer are explored deeply. Hydrogenation/hydrofluorination/fluorination can cause the planar h-BN bilayer to form a novel diamane-like monolayer by the interfacial sp3 atom bonding. These functionalized h-BN bilayers are estimated to be stable dynamically by their phonon dispersions. The functionalization on h-BN bilayer can induce its electronic nature to be transformed from an indirect wide-gap insulator to direct narrow-gap semiconductor, being desirable for its application in optoelectronics. In particular, hydrogenated and hydrofluorinated h-BN bilayers have strong absorbance coefficients for the near-infrared and visible part of the incident sunlight (larger than 105 cm-1). More interestingly, the binding energy of observed first bright exciton can achieve a value beyond 1 eV, which can effectively reduce the recombination of photogenerated electron-hole pairs. These results are potentially important for extending the applications of the h-BN bilayer in optoelectronic devices.
{"title":"Functionalized hexagonal boron nitride bilayers: Desirable electro-optical properties for optoelectronic applications","authors":"Huabing Shu","doi":"10.1039/d4cp01846j","DOIUrl":"https://doi.org/10.1039/d4cp01846j","url":null,"abstract":"Performing the PBE+G0W0+BSE calculations, structural, electronic, and optical properties of functionalized hexagonal boron nitride (h-BN) bilayer are explored deeply. Hydrogenation/hydrofluorination/fluorination can cause the planar h-BN bilayer to form a novel diamane-like monolayer by the interfacial sp3 atom bonding. These functionalized h-BN bilayers are estimated to be stable dynamically by their phonon dispersions. The functionalization on h-BN bilayer can induce its electronic nature to be transformed from an indirect wide-gap insulator to direct narrow-gap semiconductor, being desirable for its application in optoelectronics. In particular, hydrogenated and hydrofluorinated h-BN bilayers have strong absorbance coefficients for the near-infrared and visible part of the incident sunlight (larger than 105 cm-1). More interestingly, the binding energy of observed first bright exciton can achieve a value beyond 1 eV, which can effectively reduce the recombination of photogenerated electron-hole pairs. These results are potentially important for extending the applications of the h-BN bilayer in optoelectronic devices.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As a contribution to the understanding and rationalization of methodological and modeling effects in recent host-guest SAMPL challenges, using an alchemical molecular dynamics technique we have examined the impact of force field parameterization and ionic strength in connection with guest charge neutralization on the computed dissociation free energies in two typical SAMPL heavily charged macrocyclic hosts encapsulating small protonated amines with disparate binding affinities. We have shown that the methodological treatment for host neutralization, with explicit ions or with the background neutralizing plasma in the context of alchemical calculations in periodic boundary conditions, has a moderate effect on the calculated affinities. On the other hand, we have shown that seemingly small differences in the force field parameterization in highly symmetric hosts can produce systematic effects on the structural features that can have a remarkable impact on the predicted binding affinities.
{"title":"Methodological and force field effects in the molecular dynamics-based prediction of binding free energies of host-guest systems","authors":"Zhaoxi Sun, Piero Procacci","doi":"10.1039/d4cp01804d","DOIUrl":"https://doi.org/10.1039/d4cp01804d","url":null,"abstract":"As a contribution to the understanding and rationalization of methodological and modeling effects in recent host-guest SAMPL challenges, using an alchemical molecular dynamics technique we have examined the impact of force field parameterization and ionic strength in connection with guest charge neutralization on the computed dissociation free energies in two typical SAMPL heavily charged macrocyclic hosts encapsulating small protonated amines with disparate binding affinities. We have shown that the methodological treatment for host neutralization, with explicit ions or with the background neutralizing plasma in the context of alchemical calculations in periodic boundary conditions, has a moderate effect on the calculated affinities. On the other hand, we have shown that seemingly small differences in the force field parameterization in highly symmetric hosts can produce systematic effects on the structural features that can have a remarkable impact on the predicted binding affinities.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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