{"title":"乙腈基电解质的双层结构和阳离子依赖溶剂分解","authors":"Pavithra Gunasekaran, Angel Cuesta","doi":"10.1007/s10008-025-06305-1","DOIUrl":null,"url":null,"abstract":"<div><p>We present an analysis of the microscopic structure of the interface between a gold electrode and acetonitrile-based electrolytes, utilising surface-enhanced infrared absorption spectroscopy in attenuated total reflection mode (ATR-SEIRAS) combined with voltammetric data. The investigation focuses on the potential-induced changes in the interactions between interfacial acetonitrile molecules and on the onset of reductive acetonitrile decomposition in Li<sup>+</sup>- and Na<sup>+</sup>-containing electrolytes. The acetonitrile molecules exhibit a potential-dependent reorientation, leading to an increase in the concentration of antiparallel dimers at the interface at negative potentials, as the nitrogen end of the molecule is pushed away from the surface. The initial stages of reductive decomposition of acetonitrile are different in the Li<sup>+</sup>- and Na<sup>+</sup>-based electrolytes. Spectral signatures characteristic of amines are seen in LiClO<sub>4</sub> acetonitrile solutions, while amide bands are also observed in NaClO<sub>4</sub>. Because traces of water in acetonitrile must be the proton source for the reduction of interfacial acetonitrile to amines and amides, OH<sup>−</sup> must also be generated during those processes. In fact, ATR-SEIRA spectra reveal the formation and subsequent precipitation of LiOH. Precipitation of NaOH in NaClO<sub>4</sub> seems to be absent, though. With increasingly negative potential, the reductive cleavage of acetonitrile results in the formation of several cyanide species. The corresponding cyanide-characteristic bands show a potential-dependent stretching frequency that suggests they correspond to adsorbed species. These findings highlight the effect of potential-induced solvent reorientation on solvent–solvent interactions at the interface as well as the impact of the electrolyte cation on the products of the reductive decomposition of acetonitrile.</p><h3>Graphical Abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":665,"journal":{"name":"Journal of Solid State Electrochemistry","volume":"29 2024","pages":"2213 - 2224"},"PeriodicalIF":2.6000,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10008-025-06305-1.pdf","citationCount":"0","resultStr":"{\"title\":\"Double-layer structure and cation-dependent solvent decomposition in acetonitrile-based electrolytes\",\"authors\":\"Pavithra Gunasekaran, Angel Cuesta\",\"doi\":\"10.1007/s10008-025-06305-1\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>We present an analysis of the microscopic structure of the interface between a gold electrode and acetonitrile-based electrolytes, utilising surface-enhanced infrared absorption spectroscopy in attenuated total reflection mode (ATR-SEIRAS) combined with voltammetric data. The investigation focuses on the potential-induced changes in the interactions between interfacial acetonitrile molecules and on the onset of reductive acetonitrile decomposition in Li<sup>+</sup>- and Na<sup>+</sup>-containing electrolytes. The acetonitrile molecules exhibit a potential-dependent reorientation, leading to an increase in the concentration of antiparallel dimers at the interface at negative potentials, as the nitrogen end of the molecule is pushed away from the surface. The initial stages of reductive decomposition of acetonitrile are different in the Li<sup>+</sup>- and Na<sup>+</sup>-based electrolytes. Spectral signatures characteristic of amines are seen in LiClO<sub>4</sub> acetonitrile solutions, while amide bands are also observed in NaClO<sub>4</sub>. Because traces of water in acetonitrile must be the proton source for the reduction of interfacial acetonitrile to amines and amides, OH<sup>−</sup> must also be generated during those processes. In fact, ATR-SEIRA spectra reveal the formation and subsequent precipitation of LiOH. Precipitation of NaOH in NaClO<sub>4</sub> seems to be absent, though. With increasingly negative potential, the reductive cleavage of acetonitrile results in the formation of several cyanide species. The corresponding cyanide-characteristic bands show a potential-dependent stretching frequency that suggests they correspond to adsorbed species. These findings highlight the effect of potential-induced solvent reorientation on solvent–solvent interactions at the interface as well as the impact of the electrolyte cation on the products of the reductive decomposition of acetonitrile.</p><h3>Graphical Abstract</h3>\\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>\",\"PeriodicalId\":665,\"journal\":{\"name\":\"Journal of Solid State Electrochemistry\",\"volume\":\"29 2024\",\"pages\":\"2213 - 2224\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2025-04-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://link.springer.com/content/pdf/10.1007/s10008-025-06305-1.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Solid State Electrochemistry\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s10008-025-06305-1\",\"RegionNum\":4,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ELECTROCHEMISTRY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Solid State Electrochemistry","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s10008-025-06305-1","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ELECTROCHEMISTRY","Score":null,"Total":0}
Double-layer structure and cation-dependent solvent decomposition in acetonitrile-based electrolytes
We present an analysis of the microscopic structure of the interface between a gold electrode and acetonitrile-based electrolytes, utilising surface-enhanced infrared absorption spectroscopy in attenuated total reflection mode (ATR-SEIRAS) combined with voltammetric data. The investigation focuses on the potential-induced changes in the interactions between interfacial acetonitrile molecules and on the onset of reductive acetonitrile decomposition in Li+- and Na+-containing electrolytes. The acetonitrile molecules exhibit a potential-dependent reorientation, leading to an increase in the concentration of antiparallel dimers at the interface at negative potentials, as the nitrogen end of the molecule is pushed away from the surface. The initial stages of reductive decomposition of acetonitrile are different in the Li+- and Na+-based electrolytes. Spectral signatures characteristic of amines are seen in LiClO4 acetonitrile solutions, while amide bands are also observed in NaClO4. Because traces of water in acetonitrile must be the proton source for the reduction of interfacial acetonitrile to amines and amides, OH− must also be generated during those processes. In fact, ATR-SEIRA spectra reveal the formation and subsequent precipitation of LiOH. Precipitation of NaOH in NaClO4 seems to be absent, though. With increasingly negative potential, the reductive cleavage of acetonitrile results in the formation of several cyanide species. The corresponding cyanide-characteristic bands show a potential-dependent stretching frequency that suggests they correspond to adsorbed species. These findings highlight the effect of potential-induced solvent reorientation on solvent–solvent interactions at the interface as well as the impact of the electrolyte cation on the products of the reductive decomposition of acetonitrile.
期刊介绍:
The Journal of Solid State Electrochemistry is devoted to all aspects of solid-state chemistry and solid-state physics in electrochemistry.
The Journal of Solid State Electrochemistry publishes papers on all aspects of electrochemistry of solid compounds, including experimental and theoretical, basic and applied work. It equally publishes papers on the thermodynamics and kinetics of electrochemical reactions if at least one actively participating phase is solid. Also of interest are articles on the transport of ions and electrons in solids whenever these processes are relevant to electrochemical reactions and on the use of solid-state electrochemical reactions in the analysis of solids and their surfaces.
The journal covers solid-state electrochemistry and focusses on the following fields: mechanisms of solid-state electrochemical reactions, semiconductor electrochemistry, electrochemical batteries, accumulators and fuel cells, electrochemical mineral leaching, galvanic metal plating, electrochemical potential memory devices, solid-state electrochemical sensors, ion and electron transport in solid materials and polymers, electrocatalysis, photoelectrochemistry, corrosion of solid materials, solid-state electroanalysis, electrochemical machining of materials, electrochromism and electrochromic devices, new electrochemical solid-state synthesis.
The Journal of Solid State Electrochemistry makes the professional in research and industry aware of this swift progress and its importance for future developments and success in the above-mentioned fields.