Nanoparticles (NPs) of iron oxide are dispersed in mixtures of water and ionic liquid, here ethylammonium nitrate (EAN) and the interactions NP/NP and NP/solvent are studied. They are analysed by Small Angle X-Ray Scattering and Dynamic Light Scattering coupled to Forced Rayleigh Scattering from 22° C to 80° C. The NPs are well dispersed as individual objects on the whole range of composition and temperature thanks to a sufficient repulsion due to the organization of the solvents at the interface. The surface changes from hydrophilic to hydrophobic around a{proportion of 50 vol% of water: 50 vol% of EAN, following the evolution of the bulk mixtures, heterogeneous on the whole range of compositions.
{"title":"Dispersions of magnetic nanoparticles in Water/ Ionic Liquid mixtures","authors":"Thiago Fiuza, Mitradeep Sarkar, Jesse Cornelius Riedl, Fabrice Cousin, Gilles Demouchy, Jerome Depeyrot, Emmanuelle Dubois, Regine Perzynski, Veronique Peyre","doi":"10.1039/d4fd00028e","DOIUrl":"https://doi.org/10.1039/d4fd00028e","url":null,"abstract":"Nanoparticles (NPs) of iron oxide are dispersed in mixtures of water and ionic liquid, here ethylammonium nitrate (EAN) and the interactions NP/NP and NP/solvent are studied. They are analysed by Small Angle X-Ray Scattering and Dynamic Light Scattering coupled to Forced Rayleigh Scattering from 22° C to 80° C. The NPs are well dispersed as individual objects on the whole range of composition and temperature thanks to a sufficient repulsion due to the organization of the solvents at the interface. The surface changes from hydrophilic to hydrophobic around a{proportion of 50 vol% of water: 50 vol% of EAN, following the evolution of the bulk mixtures, heterogeneous on the whole range of compositions.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140576883","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}
Michael E. Ritter, Simone Alexis DeSouza, Hannah Marie Ogden, Tara J Michael, Amy S Mullin
Collisions of optically centrifuged CO2 molecules with J=244-282 (Erot =22,800-30,300 cm-1) are investigated with high-resolution transient IR absorption spectroscopy to reveal collisional and orientational phenomena of molecules with hyper-thermal rotational energies. The optical centrifuge is a non-resonant optical excitation technique that uses ultrafast, 800 nm chirped pulses to drive molecules to extreme rotational states through sequential Raman transitions. The extent of rotational excitation is controlled by tuning the optical bandwidth of the excitation pulses. Frequencies of 30 R-branch ν_3 fundamental IR probe transitions are measured for the J=186-282 states of CO2, expanding beyond previously reported IR transitions up to J=128. The optically centrifuged molecules have oriented angular momentum and unidirectional rotation. Polarization-sensitive transient IR absorption of individual rotational states of optically centrifuged molecules and their collision products reveals information about collisional energy transfer, relaxation kinetics, and dynamics of rotation-to-translation energy transfer. The transient IR probe also measures the extent of orientation and decay rates of the orientation anisotropy. Rotational energy transfer for lower energy molecules are discussed in terms of statistical models and a comparison highlights the role of increasing energy gap with J and angular momentum of the optically centrifuged molecules.
{"title":"Transient IR Spectroscopy of Optically Centrifuged CO2 (R186−R282) and Collision Dynamics for the J=244−282 States","authors":"Michael E. Ritter, Simone Alexis DeSouza, Hannah Marie Ogden, Tara J Michael, Amy S Mullin","doi":"10.1039/d3fd00179b","DOIUrl":"https://doi.org/10.1039/d3fd00179b","url":null,"abstract":"Collisions of optically centrifuged CO<small><sub>2</sub></small> molecules with J=244-282 (E<small><sub>rot</sub></small> =22,800-30,300 cm<small><sup>-1</sup></small>) are investigated with high-resolution transient IR absorption spectroscopy to reveal collisional and orientational phenomena of molecules with hyper-thermal rotational energies. The optical centrifuge is a non-resonant optical excitation technique that uses ultrafast, 800 nm chirped pulses to drive molecules to extreme rotational states through sequential Raman transitions. The extent of rotational excitation is controlled by tuning the optical bandwidth of the excitation pulses. Frequencies of 30 R-branch ν_3 fundamental IR probe transitions are measured for the J=186-282 states of CO<small><sub>2</sub></small>, expanding beyond previously reported IR transitions up to J=128. The optically centrifuged molecules have oriented angular momentum and unidirectional rotation. Polarization-sensitive transient IR absorption of individual rotational states of optically centrifuged molecules and their collision products reveals information about collisional energy transfer, relaxation kinetics, and dynamics of rotation-to-translation energy transfer. The transient IR probe also measures the extent of orientation and decay rates of the orientation anisotropy. Rotational energy transfer for lower energy molecules are discussed in terms of statistical models and a comparison highlights the role of increasing energy gap with J and angular momentum of the optically centrifuged molecules.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140576713","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}
Naomi Elstone, Emily Shaw, Karina Shimizu, Joshua Lai, Bruno Demé, Paul Lane, Matthew L Costen, Kenneth G McKendrick, Sarah Elizabeth Youngs, Sarah E. Rogers, Jose Nuno Canongia Lopes, Duncan W Bruce, John M. Slattery
As part of an ongoing study of the structure and properties of mixtures of ionic liquids in which one component has a hydrocarbon chain and the other a semiperfluorocarbon chain, we now report a study of the mixtures [C8MIM]1-x[C10MIM-F17]x[Tf2N], [C10MIM]1-x[C8MIM-F13]x[Tf2N] and [C10MIM]1-x[C10MIM-F17]x[Tf2N], where [C8MIM][Tf2N] is 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide, [C10MIM][Tf2N] is 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C8MIM-F13][Tf2N] is 1-(1H,1H,2H,2H-perfluorooctyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide and [C10MIM-F17][Tf2N] is 1-(1H,1H,2H,2H-perfluorodecyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide. The mixtures were investigated using small-angle X-ray (SAXS) and neutron (SANS) scattering complemented by molecular dynamics simulations (with viscosity and surface tension measurements also possible for the mixtures [C10MIM]1-x[C8MIM-F13]x[Tf2N]). Unlike previous studies of [C8MIM]1-x[C8MIM-F13]x[Tf2N], where no strong evidence of alkyl/fluoroalkyl chain segregation or triphilic behaviour was seen (Elstone et al., J. Phys. Chem. B, 2023, 127, 7394-7407), these new mixtures showed the formation of small aggregates of varying sizes of each component, even though all were co-miscible across the full range of compositions. Thus, while a clear polar non-polar peak (PNPP) was observed at large or small values of x, at intermediate compositions the small-angle neutron scattering at low q was dominated by scattering from these small aggregates, with little or no evidence of the PNPP at some compositions. The origins of this behaviour are discussed in terms of inter-chain interactions.
{"title":"Chain-length dependent organisation in mixtures of hydrogenous and fluorous ionic liquids","authors":"Naomi Elstone, Emily Shaw, Karina Shimizu, Joshua Lai, Bruno Demé, Paul Lane, Matthew L Costen, Kenneth G McKendrick, Sarah Elizabeth Youngs, Sarah E. Rogers, Jose Nuno Canongia Lopes, Duncan W Bruce, John M. Slattery","doi":"10.1039/d4fd00047a","DOIUrl":"https://doi.org/10.1039/d4fd00047a","url":null,"abstract":"As part of an ongoing study of the structure and properties of mixtures of ionic liquids in which one component has a hydrocarbon chain and the other a semiperfluorocarbon chain, we now report a study of the mixtures [C8MIM]1-x[C10MIM-F17]x[Tf2N], [C10MIM]1-x[C8MIM-F13]x[Tf2N] and [C10MIM]1-x[C10MIM-F17]x[Tf2N], where [C8MIM][Tf2N] is 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide, [C10MIM][Tf2N] is 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C8MIM-F13][Tf2N] is 1-(1H,1H,2H,2H-perfluorooctyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide and [C10MIM-F17][Tf2N] is 1-(1H,1H,2H,2H-perfluorodecyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide. The mixtures were investigated using small-angle X-ray (SAXS) and neutron (SANS) scattering complemented by molecular dynamics simulations (with viscosity and surface tension measurements also possible for the mixtures [C10MIM]1-x[C8MIM-F13]x[Tf2N]). Unlike previous studies of [C8MIM]1-x[C8MIM-F13]x[Tf2N], where no strong evidence of alkyl/fluoroalkyl chain segregation or triphilic behaviour was seen (Elstone et al., J. Phys. Chem. B, 2023, 127, 7394-7407), these new mixtures showed the formation of small aggregates of varying sizes of each component, even though all were co-miscible across the full range of compositions. Thus, while a clear polar non-polar peak (PNPP) was observed at large or small values of x, at intermediate compositions the small-angle neutron scattering at low q was dominated by scattering from these small aggregates, with little or no evidence of the PNPP at some compositions. The origins of this behaviour are discussed in terms of inter-chain interactions.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140577198","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}
{"title":"A Perspective on the Future of Quantum Chemical Software: The Example of the ORCA Program Package","authors":"Frank Neese","doi":"10.1039/d4fd00056k","DOIUrl":"https://doi.org/10.1039/d4fd00056k","url":null,"abstract":"TBC","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140576881","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}
Pierre-Francois Loos, Antoine Marie, Abdallah Ammar
The cumulant expansion of the Green’s function is a computationally efficient beyond-GW approach renowned for its significant enhancement of satellite features in materials. In contrast to the ubiquitous GW approximation of many-body perturbation theory, ab initio cumulant expansions performed on top of GW (GW+C) have demonstrated the capability to handle multi-particle processes by incorporating higher-order correlation effects or vertex corrections, yielding better agreements between experiment and theory for satellite structures. While widely employed in condensed matter physics, very few applications of GW+C have been published on molecular systems. Here, we assess the performance of this scheme on a series of 10-electron molecular systems (Ne, HF, H2O, NH3, and CH4) where full configuration interaction estimates of the outer-valence quasiparticle and satellite energies are available.
格林函数的累积展开是一种计算高效的超越全球定位系统的方法，因其显著增强了材料中的卫星特征而闻名。与多体扰动理论中无处不在的 GW 近似相比，在 GW（GW+C）基础上进行的 ab initio 积展开证明了通过纳入高阶相关效应或顶点校正来处理多粒子过程的能力，从而在卫星结构的实验与理论之间取得更好的一致。虽然 GW+C 广泛应用于凝聚态物理，但在分子系统中的应用却寥寥无几。在这里，我们评估了这一方案在一系列 10 电子分子系统（Ne、HF、H2O、NH3 和 CH4）上的性能，这些系统的外价准粒子和卫星能量的完全构型相互作用估计值是可用的。
{"title":"Cumulant Green's function methods for molecules","authors":"Pierre-Francois Loos, Antoine Marie, Abdallah Ammar","doi":"10.1039/d4fd00037d","DOIUrl":"https://doi.org/10.1039/d4fd00037d","url":null,"abstract":"The cumulant expansion of the Green’s function is a computationally efficient beyond-GW approach renowned for its significant enhancement of satellite features in materials. In contrast to the ubiquitous GW approximation of many-body perturbation theory, ab initio cumulant expansions performed on top of GW (GW+C) have demonstrated the capability to handle multi-particle processes by incorporating higher-order correlation effects or vertex corrections, yielding better agreements between experiment and theory for satellite structures. While widely employed in condensed matter physics, very few applications of GW+C have been published on molecular systems. Here, we assess the performance of this scheme on a series of 10-electron molecular systems (Ne, HF, H2O, NH3, and CH4) where full configuration interaction estimates of the outer-valence quasiparticle and satellite energies are available.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140576863","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 adiabatic connection (AC) approximation, along with its linearized variant AC0, was introduced as a method of obtaining dynamic correlation energy. When using a complete active space self-consistent field (CASSCF) wave function as a reference, the AC0 approximation is considered one of the most efficient multi-reference perturbation theories. It only involves the use of 1$^{st}$- and 2$^{nd}$-order reduced density matrices. However, some numerical results have indicated that the excitation energies predicted by AC0 are not as reliable as those from the second-order N-electron valence state perturbation theory (NEVPT2). In this study, we develop a spinless formulation of AC0 based on the Dyall Hamiltonian and provide a detailed comparison between AC0 and NEVPT2 approaches. We demonstrate the components within the correlation energy expressions that are common to both methods and those unique to either AC0 or NEVPT2. We investigate the role of the terms exclusive to NEVPT2 and explore the possibility of enhancing AC0's performance in this regard.
{"title":"Spinless formulation of linearized adiabatic connection approximation and its comparison with second order N-electron valence state perturbation theory","authors":"Yang Guo, Katarzyna Pernal","doi":"10.1039/d4fd00054d","DOIUrl":"https://doi.org/10.1039/d4fd00054d","url":null,"abstract":"The adiabatic connection (AC) approximation, along with its linearized variant AC0, was introduced as a method of obtaining dynamic correlation energy. When using a complete active space self-consistent field (CASSCF) wave function as a reference, the AC0 approximation is considered one of the most efficient multi-reference perturbation theories. It only involves the use of 1$^{st}$- and 2$^{nd}$-order reduced density matrices. However, some numerical results have indicated that the excitation energies predicted by AC0 are not as reliable as those from the second-order N-electron valence state perturbation theory (NEVPT2). In this study, we develop a spinless formulation of AC0 based on the Dyall Hamiltonian and provide a detailed comparison between AC0 and NEVPT2 approaches. We demonstrate the components within the correlation energy expressions that are common to both methods and those unique to either AC0 or NEVPT2. We investigate the role of the terms exclusive to NEVPT2 and explore the possibility of enhancing AC0's performance in this regard.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140602729","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 Cu2OCl2 compound has been shown to be a high-temperature spin-driven multiferroic system, with a linear magneto-electric coupling. In this paper we propose a complete study of its magnetic structure. We derive the low energy magnetic Hamiltonian using ab-initio multi-reference configuration interactions and the spin structure using Monte-Carlo simulations. Among the three magnetic structures proposed in the literature from different experimental results, our calculations support the incommensurate cycloid magnetic structure with a q=(qa,0,0) propagation vector. Using symmetry analysis, we showed that all experimental results (polarization, magnetic order, magneto-electric coupling) can be accounted for in the $Fd'd'2$ magnetic space group (2-fold axis along c).
Cu2OCl2 化合物已被证明是一种具有线性磁电耦合的高温自旋驱动多铁性体系。在本文中，我们将对其磁性结构进行全面研究。我们利用非原位多参考构型相互作用推导出了低能磁性哈密顿，并利用蒙特卡洛模拟推导出了自旋结构。在文献中根据不同的实验结果提出的三种磁结构中，我们的计算结果支持q=（qa,0,0）传播矢量的不对称摆线形磁结构。通过对称分析，我们发现所有实验结果（极化、磁序、磁电耦合）都可以在 $Fd'd'2$ 磁空间群（沿 c 的 2 倍轴）中得到解释。
{"title":"Magnetic structure of a multiferroic compound: Cu2OCl2","authors":"Julien Lévèque, Elisa Rebolini, Andrès Saùl, Marie-Bernadette Lepetit","doi":"10.1039/d4fd00042k","DOIUrl":"https://doi.org/10.1039/d4fd00042k","url":null,"abstract":"The Cu<small><sub>2</sub></small>OCl<small><sub>2</sub></small> compound has been shown to be a high-temperature spin-driven multiferroic system, with a linear magneto-electric coupling. In this paper we propose a complete study of its magnetic structure. We derive the low energy magnetic Hamiltonian using ab-initio multi-reference configuration interactions and the spin structure using Monte-Carlo simulations. Among the three magnetic structures proposed in the literature from different experimental results, our calculations support the incommensurate cycloid magnetic structure with a <strong>q</strong>=(q<small><sub>a</sub></small>,0,0) propagation vector. Using symmetry analysis, we showed that all experimental results (polarization, magnetic order, magneto-electric coupling) can be accounted for in the $Fd'd'2$ magnetic space group (2-fold axis along <strong>c</strong>).","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140313199","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}
Nicole M Braunscheidel, Arnab Bachhar, Nicholas J. Mayhall
The task of computing wavefunctions that are accurate, yet simple enough mathematical objects to use for reasoning has long been a challenge in quantum chemistry. The difficulty in drawing physical conclusions from a wavefunction is often related to the generally large number of configurations with similar weights. In Tensor Product Selected CI, we use a locally correlated tensor product state basis, which has the effect of concentrating the weight of a state onto a smaller number of physically interpretable degrees of freedom. In this paper, we apply TPSCI to a series of three molecular systems ranging in separability, one of which is the first application of TPSCI to an open-shell bimetallic system. For each of these systems, we obtain accurate solutions to large active spaces, and analyze the resulting wavefunctions through a series of different approaches including (i) direct inspection of the TPS basis coefficients, (ii) construction of Bloch effective Hamiltonians, and (iii) computation of cluster correlation functions.
{"title":"Accurate and Interpretable Representation of Correlated Electronic Structure via Tensor Product Selected CI","authors":"Nicole M Braunscheidel, Arnab Bachhar, Nicholas J. Mayhall","doi":"10.1039/d4fd00049h","DOIUrl":"https://doi.org/10.1039/d4fd00049h","url":null,"abstract":"The task of computing wavefunctions that are accurate, yet simple enough mathematical objects to use for reasoning has long been a challenge in quantum chemistry. The difficulty in drawing physical conclusions from a wavefunction is often related to the generally large number of configurations with similar weights. In Tensor Product Selected CI, we use a locally correlated tensor product state basis, which has the effect of concentrating the weight of a state onto a smaller number of physically interpretable degrees of freedom. In this paper, we apply TPSCI to a series of three molecular systems ranging in separability, one of which is the first application of TPSCI to an open-shell bimetallic system. For each of these systems, we obtain accurate solutions to large active spaces, and analyze the resulting wavefunctions through a series of different approaches including (i) direct inspection of the TPS basis coefficients, (ii) construction of Bloch effective Hamiltonians, and (iii) computation of cluster correlation functions.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140324845","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}
Li-S batteries have attracted attention as next-generation rechargeable batteries owing to their high theoretical capacity and cost-effectiveness. Sparingly solvating electrolytes hold promise because they suppress the dissolution and shuttling of polysulfide intermediates to increase the Coulombic efficiency and extend the cycle life. This study investigated the solubility of polysulfide (Li2S8) in a range of liquid electrolytes, including organic electrolytes, highly concentrated electrolytes, and ionic liquids. The Li2S8 solubility was well correlated with the donor number (DNNMR), estimated via 23Na-NMR, and was lower than 100 mM_(elemental sulfur) in electrolytes with DNNMR<14, regardless of the type of electrolyte. Highly concentrated electrolytes comprising lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and linear chain dialkyl ethers such as methylpropyl ether (MPE), n-butylmethyl ether (BME), and ethyl propyl ether (EPE) were studied as sparignly solvating electrolytes for Li-S batteries. Monomethyl ethers, such as BME, showed more pronounced Li-ion coordination and higher ionic conductivity, whereas the steric hindrance of longer alkyl chains in EPE lowered the solvation number, enhanced ion association, and lowered the ionic conductivity despite the solvents having similar dielectric constants. The charge-discharge rate capabilities of Li-S cells with dialkyl ether-based electrolytes were more impressive than those of cells with a localized high-concentration electrolyte using sulfolane (SL) and hydrofluoroether (HFE), [Li(SL)2][TFSA]-2HFE. The higher rate performance was attributed to the superior Li-ion transport properties of the dialkyl ether-based electrolytes. A pouch-type cell using lightweight [Li(BME)3][TFSA] demonstrated an energy density exceeding 300 Wh kg-1 under lean electrolyte conditions.
{"title":"Linear ether-based highly concentrated electrolytes for Li-sulfur batteries","authors":"Toru Ishikawa, Shohei Haga, Keisuke Shigenobu, Taku Sudoh, Seiji Tsuzuki, Wataru Shinoda, Kaoru Dokko, Masayoshi Watanabe, Kazuhide Ueno","doi":"10.1039/d4fd00024b","DOIUrl":"https://doi.org/10.1039/d4fd00024b","url":null,"abstract":"Li-S batteries have attracted attention as next-generation rechargeable batteries owing to their high theoretical capacity and cost-effectiveness. Sparingly solvating electrolytes hold promise because they suppress the dissolution and shuttling of polysulfide intermediates to increase the Coulombic efficiency and extend the cycle life. This study investigated the solubility of polysulfide (Li<small><sub>2</sub></small>S<small><sub>8</sub></small>) in a range of liquid electrolytes, including organic electrolytes, highly concentrated electrolytes, and ionic liquids. The Li<small><sub>2</sub></small>S<small><sub>8</sub></small> solubility was well correlated with the donor number (DN<small><sub>NMR</sub></small>), estimated via <small><sup>23</sup></small>Na-NMR, and was lower than 100 mM_(elemental sulfur) in electrolytes with DN<small><sub>NMR</sub></small><14, regardless of the type of electrolyte. Highly concentrated electrolytes comprising lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and linear chain dialkyl ethers such as methylpropyl ether (MPE), n-butylmethyl ether (BME), and ethyl propyl ether (EPE) were studied as sparignly solvating electrolytes for Li-S batteries. Monomethyl ethers, such as BME, showed more pronounced Li-ion coordination and higher ionic conductivity, whereas the steric hindrance of longer alkyl chains in EPE lowered the solvation number, enhanced ion association, and lowered the ionic conductivity despite the solvents having similar dielectric constants. The charge-discharge rate capabilities of Li-S cells with dialkyl ether-based electrolytes were more impressive than those of cells with a localized high-concentration electrolyte using sulfolane (SL) and hydrofluoroether (HFE), [Li(SL)<small><sub>2</sub></small>][TFSA]-2HFE. The higher rate performance was attributed to the superior Li-ion transport properties of the dialkyl ether-based electrolytes. A pouch-type cell using lightweight [Li(BME)<small><sub>3</sub></small>][TFSA] demonstrated an energy density exceeding 300 Wh kg<small><sup>-1</sup></small> under lean electrolyte conditions.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140299659","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}
Edgar Josue Landinez-Borda, Kenneth O. Berard, Annette Lopez, Brenda M Rubenstein
Key to being able to accurately model the properties of realistic materials is being able to predict their properties in the thermodynamic limit. Nevertheless, because most many-body electronic structure methods scale as a high-order polynomial, or even exponentially, with system size, directly simulating large systems in their thermodynamic limit rapidly becomes computationally intractable. As a result, researchers typically estimate the properties of large systems that approach the thermodynamic limit by extrapolating the properties of smaller, computationally-accessible systems based on relatively simple scaling expressions. In this work, we employ Gaussian processes to more accurately and efficiently extrapolate many-body simulations to their thermodynamic limit. We train our Gaussian processes on Smooth Overlap of Atomic Positions (SOAP) descriptors to extrapolate the energies of one-dimensional hydrogen chains obtained using two, high-accuracy many-body methods: Coupled Cluster theory and Auxiliary Field Quantum Monte Carlo (AFQMC). In so doing, we show that Gaussian processes trained on relatively short, 10-30-atom chains can predict the energies of both homogeneous and inhomogeneous hydrogen chains in their thermodynamic limit with sub-milliHartree accuracy. Unlike standard scaling expressions, our GPR-based approach is highly generalizable given representative training data and is not dependent on systems' geometries or dimensionality. This work highlights the potential for machine learning to correct for the finite size effects that routinely complicate the interpretation of finite size many-body simulations.
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