Electrochemical Behavior of (NH2)2CO–(NH4)2SiF6 Melt

Electrochemical Behavior of (NH2)2CO–(NH4)2SiF6 Melt | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Electrochemical Behavior of (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 Melt SERGEI DEVYATKIN, Fan Meng, Serhii Kuleshov, Ruopeng Li, Peixia Yang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5278871/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The solubility of silicon oxides and fluorides in ionic-organic melts ((NH 2 ) 2 CO, CH 3 CONH 2 and С 3 H 4 N 2 ) has been studied. For electrochemical investigations, the system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 was chosen. Voltammetric studies showed that the most electropositive electrochemical process in the (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 melt is the discharge of ions of silicon in the oxidation state (IV) to silicon in the oxidation state (II) followed by the formation of elemental silicon. Micron coatings of silicon on Ni and stainless steel have been obtained by electrolysis of a (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 melt at 120 ° С. Silicon Electrochemistry Ion-organic melts Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1 Introduction Silicon possesses quite a number of properties which distinguish it from other elements of the periodic table: high melting point (t m = 1415°C), average density 2.33 g/cm 3 , high reactivity, photosensitivity and photovoltaic properties. Silicon also possesses semiconductor properties; its resistance decreases with rising temperature. Silicon is used in metallurgy, semiconductor industry; monocrystalline silicon of high purity is the main raw material for solar power industry etc. One of methods for producing silicon [ 1 ] as powder [ 2 ], coatings [ 3 ], alloys [ 4 ] and refractory compounds [ 5 ] is the electrolysis of molten salts. Silumin, Al-Si alloys, is produced by the electrolysis of cryolite-alumina melts with additions of silica at 1000 °С [ 4 ]. The production of silicon and its refractory compounds by electrolysis of chloro-fluoride melts at 700 °С has been studied in quite a number of works [ 5 – 8 ]. Reference [ 9 ] explored the possibility of producing silicon by electrolysis in the solution tetrabutylammonium chloride-tetrabutylammonium tetraphenylborate-Si(NCO) 4 at 25–150 °С. The electrodeposition of silicon in organic solvent containing silicon chloride was studied in quite a number of works [ 10 – 12 ]. The electrochemical production of silicon was studied at room temperature in ionic liquids [ 13 ]. To date, most ionic liquids are still prohibitively expensive for industrial applications. The aim of this work was to study the electrochemical behavior of silicon ions in ionic-organic melts and to explore the possibility of electrochemically producing elemental silicon. 2 Experimental The solubility of silicon oxides and fluorides in ionic-organic melts (NH 2 ) 2 CO, CH 3 CONH 2 and С 3 H 4 N 2 ) was studied by isothermal saturation method. The electrochemical behavior of silicon in ionic-organic melts was studied by cyclic voltammetry. The electrochemical experiments were performed in a quartz cell in air and Ar (Wuhan Newradar Trade Company Limited 99.995%) at 120–135 °С. All salts used for the investigations were chemically pure: (NH 2 ) 2 CO (Shanghai Synnad Chemical Co. 99.0%), CH 3 CONH 2 (Simbias Ukraine 99.0%), C 3 H 4 N 2 (Shanghai Synnad Chemical Co. 99.5%), SiO 2 (Sigma-Aldrich 99.0%), K 2 SiF 6 (Sigma-Aldrich 99.0%), (NH 4 ) 2 SiF 6 (Sigma-Aldrich 98.0%). All salts were used as received and was dried over P 2 O 5 in dry glovebox for several days. The voltammetric studies were carried out in a glassy carbon crucible (SU-2000), with respect to an Ag/AgNO 3 (0.1 wt%) reference electrode. The working electrode was a glassy carbon (SU-2000) rod (S = 0.4–0.6 cm 2 ). The voltammetric studies were carried out using a potentiostat CHI760E (Shanghai Chenhua Instrument Co. Ltd., China). The electrolysis experiments were performed in a quartz cell in air or Ar, stainless steel and Ni plates were used as cathodes. A glassy carbon crucible served as the anode and a container for the melt. The cathodic products were analyzed by XRD and SEM (JEM 2100F - JEOL, SUPRA 55VP – Carl Zeiss AG). 3 Results and Discussion Silica (SiO 2 ) and alkali metal hexafluorosilicates (K 2 SiF 6 ) are insoluble in ionic-organic melts (NH 2 ) 2 CO, CH 3 CONH 2 and С 3 H 4 N 2 ) at 120–135 °C. Ammonium hexafluorosilicate (NH 4 ) 2 SiF 6 is soluble in molten carbamide at 135 °С to 10 wt.%; the melting temperature of the binary system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 decreases with increasing ammonium hexafluorosilicate concentration, which makes it possible to carry out investigations at 120 °C. Cyclic voltammetry is one of main experimental methods of electrochemistry. It makes it possible not only to determine the electrolysis conditions (current density, potential), but also to determine the stages and kinetic parameters of the electrochemical process under study. A typical cyclic voltammogram for the binary system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 at 135 °С is shown in Figure 1. The voltammogram exhibit in the cathodic region a process that is more electropositive than carbamide decomposition. The voltammograms in the (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 melts at 135 °С exhibited a peak in the cathodic region, where limiting current depended on the concentration of (NH 4 ) 2 SiF 6 in the melts (Figure 2). Figure 3. shows cyclic voltammograms in a (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 melt as a function of scan rate. An inverse dependence of the current function on the scan rate can be seen. This indicated an increase in Si(IV) concentration in the melt at slow scan rates. This is possible due to the disproportionation reaction of the Si(II) reduction product. The diagnostic criterion for the current function (i p /v 1/2 ) versus scan rate points to the ECE mechanism (Figure 4) [14]. The dependence of the limiting current function and peak potential on the scan rate and absence of the anodic peak indicate the observed electrochemical process to be irreversible. The electrolysis of the melt resulted in the formation of a metal-like cathode deposit. It is impossible to determine the kinetic parameters of the observed process because the concentration of the electrochemically active substance changes during measurement. From the foregoing it can be concluded that silicon in the oxidation state (IV) is reduced in the binary system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 to silicon in the oxidation state (II) with subsequent disproportionation reaction to form elemental silicon. Based on voltametric investigations, electrolysis experiments were carried out. The electrolysis was carried out under galvanostatic conditions in wide current density range of 10–60 mA/cm 2 in air or in Ar. At current densities 20–30 mA/cm 2 , thin films were obtained (Figure 5). Conducting electrolysis experiments in air or in Ar did not affect the composition and thickness of the cathodic product. Figures 6. and 7. shows morphologies of a coating obtained by electrolysis of the binary system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 (6 wt.%) at 120 °С and a current density 20 mA/cm 2 and chemical maps of elemental silicon distribution over the surface of Ni and stainless steel samples. After the electrolysis experiments, the melt was washed with a weak HCl solution. The remaining dry residue was rinsed with a distillate and alcohol. After drying, the resulting powder was analyzed by XRD and SEM. The XRD phase analysis of powder after the electrolysis of an ionic-organic melt did not allow us to determine the composition of the coating because it was very fine-crystalline. In order to coarsen the crystal structure of the powder, the samples were annealed in a furnace at 700 °C in Ar stream. Figures 8a. and 8b. shows morphologies of a powder obtained by electrolysis of the binary system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 (6 wt.%) and after annealing at 700 °С in an Ar. The powder is obtained in the form of stratified layers (flakes) [15- 17]. The research has established that the XRD patterns of the powder obtained by electrolysis (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 at 120 °C and after annealing at 700 °С in an Ar stream exhibits peaks corresponds to the Si (ICDD PDF-2 – #00-027-1402). Silicon crystallizes in the cubic Fd3m space group (Figure 9). The sample was obtained without extraneous phases inclusions. On the basis of XRD and SEM analyses it may be assumed that the deposited coatings and powder from binary system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 is silicon. 4 Conclusions Based on data on the solubility of silicon salts in ionic-organic melts, the binary system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 was chosen for electrochemical investigations. The discharge mechanism and conditions of Si(IV) at 135 °С have been studied by cyclic voltammetry. Silicon in the oxidation state (IV) is discharged at the cathode in one stage to silicon in the oxidation state (II) with subsequent disproportionation reaction to form elemental silicon. Powder and micron coatings deposits of silicon have been obtained by the electrolysis of a system (NH 2 ) 2 CO–(NH 4 ) 2 SiF 6 at 120 °С. Declarations No funding was received to assist with the preparation of this manuscript. Author Contribution S.D. and P.Y. wrote the main manuscript text F.M. and S.K. prepared figures 1-4,9. F.M. and R.L. prepared figures 5-8. All authors reviewed the manuscript References Federico Faggin (2021) Silicon: From the Invention of the Microprocessor to the New Science of Consciousness. Waterside Productions. https://doi.org/10.31275/20212205 Andriiko A.A., Panov E.V., Boiko O.I., Yakovlev B.V., Borovik O.Ya. (1997) Dependence of the K 2 SiF 6 content in the cathodic deposit on the melt composition during electrodeposition of powder-like silicon from the KCl–KF–K 2 SiF 6 melt containing silicon dioxide. Russ. J. Electrochem. 33: 1343–1345. Muhammad M.I., Imane A., Cherif M., Takeaki S., Mohamed K., Saad H., Katsuhiro A. (2018) Electrodeposition and characterization of silicon films obtained through electrochemical reduction of SiO 2 nanoparticles. Thin Solid Films. 654: 1–10. https://doi.org/10.1016/j.tsf.2018.03.072 Awayssa O., Saevarsdottir G., Meirbekova R., Haarberg G.M. (2021) Electrochemical Production of Al-Si Alloys in Cryolitic Melts in a Laboratory Cell. J. Electrochem. Soc. 168: 046506. https://doi.org/10.1149/1945-7111/abf40e Kurt H. Stem (1996) Metallurgical and Ceramic Protective Coatings. 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Soc. 63: H3101–H3109. https://doi.org/10.1149/2.0151604jes Shoshani Y., Jerby E. (2022) Microwave-ignited DC-plasma ejection from basalt: Powder-generation and lightning-like effects. Appl. Phys. Lett. 120: 264101. https://doi.org/10.1063/5.0096020 Jian L., Fang G., Li Zh., Kai X., Zhang D., Chen Zh., Humphries S., Heness G., Yeung W.Y. (2011) An approach to the uniform dispersion of a high volume fraction of carbon nanotubes in aluminum powder. Carbon. 49: 1965-1971. https://doi.org/10.1016/j.carbon.2011.01.021 Gilmore C.J., Kaduk J.A., Schenk H. (2019)International Tables for Crystallography Volume H: Powder diffraction. Wiley. https://doi.org/10.1107/97809553602060000115 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5278871","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":384658335,"identity":"7e4ad133-4026-4d6e-a519-bf408fb6fe95","order_by":0,"name":"SERGEI DEVYATKIN","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvElEQVRIiWNgGAWjYDCCA2AygYeBvYEkLQlALTwHSNTCwCCRQKQOvuM9ZhI/f6TJmEs+3niDocYmmqAWyTNnzCR7EnJ4LGenFVswHEvLbSCkxeBGWpoET0IFj8HtHDMJxobDRGi5/yxN8g9Iy80zxGq5wXxMmgfoMIMbPERqkTyTfNhaJi2Nx+AM0C8JxPiF7/jBxptvbJLtDY4f3njjQ40NYS1AwCIBcyTRUcP8Aa6FSB2jYBSMglEwwgAANjI/hbYDDLoAAAAASUVORK5CYII=","orcid":"","institution":"Harbin Institute of Technology","correspondingAuthor":true,"prefix":"","firstName":"SERGEI","middleName":"","lastName":"DEVYATKIN","suffix":""},{"id":384658336,"identity":"099b08c1-42a5-4bc2-9417-d5342698ec9a","order_by":1,"name":"Fan Meng","email":"","orcid":"","institution":"Harbin Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Fan","middleName":"","lastName":"Meng","suffix":""},{"id":384658338,"identity":"8c3d27aa-0431-48ba-9a83-d52fc0b25baf","order_by":2,"name":"Serhii Kuleshov","email":"","orcid":"","institution":"V.I. 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01:38:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5278871/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5278871/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":71367474,"identity":"f4b2d0e1-b15c-4342-85ee-01c2e5a39432","added_by":"auto","created_at":"2024-12-13 18:02:34","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":29336,"visible":true,"origin":"","legend":"\u003cp\u003eCyclic voltammogram for the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6 \u003c/sub\u003e(3.05×10\u003csup\u003e-4\u003c/sup\u003e\u0026nbsp;mol/cm\u003csup\u003e3\u003c/sup\u003e) at 135\u0026nbsp;°С, v=0.001 V/s, S=0.47 cm\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/67705c55d5e4cf080862dec3.png"},{"id":71368962,"identity":"8dd00310-969e-417f-82f7-d566fdbd9419","added_by":"auto","created_at":"2024-12-13 18:26:34","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":35262,"visible":true,"origin":"","legend":"\u003cp\u003eCyclic voltammograms for the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e at 135\u0026nbsp;°С at different silicon salts concentrations (mol/cm\u003csup\u003e3\u003c/sup\u003e): 1 – 0; 2 – 6.1×10\u003csup\u003e-5\u003c/sup\u003e, 3 – 1.2×10\u003csup\u003e-4\u003c/sup\u003e, 4 – 4.8×10\u003csup\u003e-4\u003c/sup\u003e, v = 0.001 V/s; S = 0.47 cm\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/64d8a8cd4a16cca2a7717f6b.png"},{"id":71368031,"identity":"66911e6d-5771-4a24-b1d5-6178c844eb4f","added_by":"auto","created_at":"2024-12-13 18:10:34","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":28424,"visible":true,"origin":"","legend":"\u003cp\u003eCyclic voltammograms for the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (4.8×10\u003csup\u003e-4\u003c/sup\u003e mol/cm\u003csup\u003e3\u003c/sup\u003e) at different scan rates at 135\u0026nbsp;°С; S=0.47 cm\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/90866c821b4af41ad8038437.png"},{"id":71368287,"identity":"90808264-835b-4ba3-be3f-8731dc44327a","added_by":"auto","created_at":"2024-12-13 18:18:34","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":27597,"visible":true,"origin":"","legend":"\u003cp\u003eDependence of the current function (i\u003csub\u003ep\u003c/sub\u003e/v\u003csup\u003e1/2\u003c/sup\u003e) on the scan rate of the observed wave in the system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (4.8×10\u003csup\u003e-4\u003c/sup\u003e mol/cm\u003csup\u003e3\u003c/sup\u003e) at 135\u0026nbsp;°С.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/2ced5db1ebee663adff967fb.png"},{"id":71368028,"identity":"eefca9a4-db95-4a38-964d-fdc0f82853c8","added_by":"auto","created_at":"2024-12-13 18:10:34","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":83121,"visible":true,"origin":"","legend":"\u003cp\u003eNi sample after the electrolysis of the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (6 wt.%) at 120\u0026nbsp;°С in air and a current density 20 mA/cm\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/a9f98791466b0c0b123a18ad.png"},{"id":71367482,"identity":"337d8a20-c6dc-45a2-a5db-bade63d20c87","added_by":"auto","created_at":"2024-12-13 18:02:34","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":143826,"visible":true,"origin":"","legend":"\u003cp\u003eMorphology of a coating (а) obtained by electrolysis of the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (6 wt.%) at 120\u0026nbsp;°С and a current density 20\u0026nbsp;mA/cm\u003csup\u003e2\u003c/sup\u003e and chemical map (b) of elemental silicon distribution over the Ni sample surface.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/49b695e6d21948ebb5a4835f.png"},{"id":71367477,"identity":"61c1ec14-cb8c-4867-a747-3474d5728ee6","added_by":"auto","created_at":"2024-12-13 18:02:34","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":118965,"visible":true,"origin":"","legend":"\u003cp\u003eMorphology of a coating (а) obtained by electrolysis of the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (6\u0026nbsp;wt.%) at 120\u0026nbsp;°С and a current density 30 mA/cm\u003csup\u003e2\u003c/sup\u003e and chemical map (b) of elemental silicon distribution over the stainless steel sample surface.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/25c67769470f88a2401d3eee.png"},{"id":71367481,"identity":"da6416c8-d46d-47ff-afb3-a743d333100e","added_by":"auto","created_at":"2024-12-13 18:02:34","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":166522,"visible":true,"origin":"","legend":"\u003cp\u003eMorphology of a powder obtained by electrolysis of the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (6\u0026nbsp;wt.%) at 120\u0026nbsp;°С and after annealing at 700\u0026nbsp;°С in an Ar.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/b8e5f2fd22b32a4cc9ff98c4.png"},{"id":71368289,"identity":"2aa541b3-4db7-4f81-9b6e-4dcc9d3ddd43","added_by":"auto","created_at":"2024-12-13 18:18:34","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":26042,"visible":true,"origin":"","legend":"\u003cp\u003eX-ray pattern of a powder deposited from a ternary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e at 120\u0026nbsp;°C and after annealing at 700°С in an Ar stream\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/13365cde3ac66491947e02f4.png"},{"id":74945923,"identity":"b7e27dd1-8248-4011-a8cb-df259a5fa8f5","added_by":"auto","created_at":"2025-01-28 15:32:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1066927,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5278871/v1/d32b75ce-540b-48be-b664-6bf23f32c5dd.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eElectrochemical Behavior of (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e Melt\u003c/p\u003e","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eSilicon possesses quite a number of properties which distinguish it from other elements of the periodic table: high melting point (t\u003csub\u003em\u003c/sub\u003e = 1415\u0026deg;C), average density 2.33 g/cm\u003csup\u003e3\u003c/sup\u003e, high reactivity, photosensitivity and photovoltaic properties. Silicon also possesses semiconductor properties; its resistance decreases with rising temperature. Silicon is used in metallurgy, semiconductor industry; monocrystalline silicon of high purity is the main raw material for solar power industry etc. One of methods for producing silicon [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] as powder [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], coatings [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], alloys [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] and refractory compounds [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] is the electrolysis of molten salts. Silumin, Al-Si alloys, is produced by the electrolysis of cryolite-alumina melts with additions of silica at 1000 \u0026deg;С [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The production of silicon and its refractory compounds by electrolysis of chloro-fluoride melts at 700 \u0026deg;С has been studied in quite a number of works [\u003cspan additionalcitationids=\"CR6 CR7\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Reference [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] explored the possibility of producing silicon by electrolysis in the solution tetrabutylammonium chloride-tetrabutylammonium tetraphenylborate-Si(NCO)\u003csub\u003e4\u003c/sub\u003e at 25\u0026ndash;150 \u0026deg;С. The electrodeposition of silicon in organic solvent containing silicon chloride was studied in quite a number of works [\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The electrochemical production of silicon was studied at room temperature in ionic liquids [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. To date, most ionic liquids are still prohibitively expensive for industrial applications. The aim of this work was to study the electrochemical behavior of silicon ions in ionic-organic melts and to explore the possibility of electrochemically producing elemental silicon.\u003c/p\u003e"},{"header":"2 Experimental","content":"\u003cp\u003eThe solubility of silicon oxides and fluorides in ionic-organic melts (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO, CH\u003csub\u003e3\u003c/sub\u003eCONH\u003csub\u003e2\u003c/sub\u003e and С\u003csub\u003e3\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eN\u003csub\u003e2\u003c/sub\u003e) was studied by isothermal saturation method. The electrochemical behavior of silicon in ionic-organic melts was studied by cyclic voltammetry. The electrochemical experiments were performed in a quartz cell in air and Ar (Wuhan Newradar Trade Company Limited 99.995%) at 120\u0026ndash;135 \u0026deg;С. All salts used for the investigations were chemically pure: (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO (Shanghai Synnad Chemical Co. 99.0%), CH\u003csub\u003e3\u003c/sub\u003eCONH\u003csub\u003e2\u003c/sub\u003e (Simbias Ukraine 99.0%), C\u003csub\u003e3\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eN\u003csub\u003e2\u003c/sub\u003e (Shanghai Synnad Chemical Co. 99.5%), SiO\u003csub\u003e2\u003c/sub\u003e (Sigma-Aldrich 99.0%), K\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (Sigma-Aldrich 99.0%), (NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (Sigma-Aldrich 98.0%). All salts were used as received and was dried over P\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e in dry glovebox for several days. The voltammetric studies were carried out in a glassy carbon crucible (SU-2000), with respect to an Ag/AgNO\u003csub\u003e3\u003c/sub\u003e (0.1 wt%) reference electrode. The working electrode was a glassy carbon (SU-2000) rod (S\u0026thinsp;=\u0026thinsp;0.4\u0026ndash;0.6 cm\u003csup\u003e2\u003c/sup\u003e). The voltammetric studies were carried out using a potentiostat CHI760E (Shanghai Chenhua Instrument Co. Ltd., China). The electrolysis experiments were performed in a quartz cell in air or Ar, stainless steel and Ni plates were used as cathodes. A glassy carbon crucible served as the anode and a container for the melt. The cathodic products were analyzed by XRD and SEM (JEM 2100F - JEOL, SUPRA 55VP \u0026ndash; Carl Zeiss AG).\u003c/p\u003e"},{"header":"3 Results and Discussion","content":"\u003cp\u003eSilica (SiO\u003csub\u003e2\u003c/sub\u003e) and alkali metal hexafluorosilicates (K\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e) are insoluble in ionic-organic melts (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO, CH\u003csub\u003e3\u003c/sub\u003eCONH\u003csub\u003e2\u003c/sub\u003e and С\u003csub\u003e3\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eN\u003csub\u003e2\u003c/sub\u003e) at\u0026nbsp;120\u0026ndash;135\u0026nbsp;\u0026deg;C. Ammonium hexafluorosilicate (NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e is soluble in molten carbamide at 135\u0026nbsp;\u0026deg;С\u0026nbsp;to 10 wt.%; the melting temperature\u0026nbsp;of the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u0026nbsp;\u003c/sub\u003edecreases with increasing ammonium hexafluorosilicate concentration, which makes it possible to carry out investigations at 120\u0026nbsp;\u0026deg;C.\u003c/p\u003e\n\u003cp\u003eCyclic voltammetry is one of main experimental methods of electrochemistry. It makes it possible not only to determine the electrolysis conditions (current density, potential), but also to determine the stages and kinetic parameters of the electrochemical process under study.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA typical cyclic voltammogram for the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u0026nbsp;\u003c/sub\u003eat 135 \u0026deg;С is shown in Figure 1. The voltammogram exhibit in the cathodic region a process that is more electropositive than carbamide decomposition.\u003c/p\u003e\n\u003cp\u003eThe voltammograms in the (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u0026nbsp;\u003c/sub\u003emelts at 135\u0026nbsp;\u0026deg;С exhibited a peak in the cathodic region, where limiting current depended on the concentration of (NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e in the melts (Figure 2).\u003c/p\u003e\n\u003cp\u003eFigure 3. shows cyclic voltammograms in a (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e melt as a function of scan rate. An inverse dependence of the current function on the scan rate can be seen. This indicated an increase in Si(IV) concentration in the melt at slow scan rates. This is possible due to the disproportionation reaction of the Si(II) reduction product.\u003c/p\u003e\n\u003cp\u003eThe diagnostic criterion for the current function (i\u003csub\u003ep\u003c/sub\u003e/v\u003csup\u003e1/2\u003c/sup\u003e) versus scan rate points to the ECE mechanism (Figure 4) [14].\u003c/p\u003e\n\u003cp\u003eThe dependence of the limiting current function and peak potential on the scan rate and absence of the anodic peak indicate the observed electrochemical process to be irreversible. The electrolysis of the melt resulted in the formation of a metal-like cathode deposit. It is impossible to determine the kinetic parameters of the observed process because the concentration of the electrochemically active substance changes during measurement.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFrom the foregoing it can be concluded that silicon in the oxidation state (IV) is reduced in the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e to silicon in the oxidation state (II) with subsequent disproportionation reaction to form elemental silicon.\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"405\" height=\"56\"\u003e\u003c/p\u003e\n\u003cp\u003eBased on voltametric investigations, electrolysis experiments were carried out. The electrolysis was carried out under galvanostatic conditions in wide current density range of 10\u0026ndash;60 mA/cm\u003csup\u003e2\u003c/sup\u003e in air or in Ar. At current densities 20\u0026ndash;30 mA/cm\u003csup\u003e2\u003c/sup\u003e, thin films were obtained (Figure 5). Conducting electrolysis experiments in air or in Ar did not affect the composition and thickness of the cathodic product.\u003c/p\u003e\n\u003cp\u003eFigures\u0026nbsp;6. and 7. shows morphologies of a coating obtained by electrolysis of the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (6 wt.%) at 120 \u0026deg;С and a current density 20 mA/cm\u003csup\u003e2\u003c/sup\u003e and chemical maps of elemental silicon distribution over the surface of Ni and stainless steel samples.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAfter the electrolysis experiments, the melt was washed with a weak HCl solution. The remaining dry residue was rinsed with a distillate and alcohol. After drying, the resulting powder was analyzed by XRD and SEM.\u0026nbsp;The XRD phase analysis of powder after the electrolysis of an ionic-organic melt did not allow us to determine the composition of the coating because it was very fine-crystalline. In order to coarsen the crystal structure of the powder, the samples were annealed in a furnace at 700 \u0026deg;C in Ar stream.\u0026nbsp;Figures\u0026nbsp;8a. and 8b. shows morphologies of a powder obtained by electrolysis of the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e (6 wt.%) and after annealing at 700 \u0026deg;С in an Ar. The powder is obtained in the form of stratified layers (flakes) [15- 17].\u003c/p\u003e\n\u003cp\u003eThe research has established that the XRD patterns of the powder obtained by electrolysis\u0026nbsp;(NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e at 120 \u0026deg;C and after annealing at 700 \u0026deg;С in an Ar stream exhibits peaks corresponds to the Si (ICDD PDF-2 \u0026ndash; #00-027-1402). Silicon crystallizes in the cubic Fd3m space group (Figure 9). The sample was obtained without extraneous phases inclusions.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOn the basis of\u0026nbsp;XRD and SEM analyses it may be assumed that the deposited coatings and powder from binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e is silicon.\u003c/p\u003e"},{"header":"4 Conclusions","content":"\u003cp\u003eBased on data on the solubility of silicon salts in ionic-organic melts, the binary system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e was chosen for electrochemical investigations. The discharge mechanism and conditions of Si(IV) at 135 \u0026deg;С have been studied by cyclic voltammetry. Silicon in the oxidation state (IV) is discharged at the cathode in one stage to silicon in the oxidation state (II) with subsequent disproportionation reaction to form elemental silicon. Powder and micron coatings deposits of silicon have been obtained by the electrolysis of a system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO\u0026ndash;(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e at 120 \u0026deg;С.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eNo funding was received to assist with the preparation of this manuscript.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eS.D. and P.Y. wrote the main manuscript text F.M. and S.K. prepared figures 1-4,9. F.M. and R.L. prepared figures 5-8. All authors reviewed the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eFederico Faggin (2021) Silicon: From the Invention of the Microprocessor to the New Science of Consciousness. Waterside Productions. \u003cstrong\u003ehttps://doi.org/10.31275/20212205\u003c/strong\u003e\u003c/li\u003e\n\u003cli\u003eAndriiko A.A., Panov E.V., Boiko O.I., Yakovlev B.V., Borovik O.Ya. (1997) Dependence of the K\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e content in the cathodic deposit on the melt composition during electrodeposition of powder-like silicon from the KCl\u0026ndash;KF\u0026ndash;K\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e melt containing silicon dioxide. Russ. J. Electrochem. 33: 1343\u0026ndash;1345.\u003c/li\u003e\n\u003cli\u003eMuhammad M.I., Imane A., Cherif M., Takeaki S., Mohamed K., Saad H., Katsuhiro A. (2018) Electrodeposition and characterization of silicon films obtained through electrochemical reduction of SiO\u003csub\u003e2\u003c/sub\u003e nanoparticles. Thin Solid Films. 654: 1\u0026ndash;10. https://doi.org/10.1016/j.tsf.2018.03.072 \u003c/li\u003e\n\u003cli\u003eAwayssa O., Saevarsdottir G., Meirbekova R., Haarberg G.M. (2021) Electrochemical Production of Al-Si Alloys in Cryolitic Melts in a Laboratory Cell. J. Electrochem. Soc. 168: 046506. https://doi.org/10.1149/1945-7111/abf40e\u003c/li\u003e\n\u003cli\u003eKurt H. Stem (1996) Metallurgical and Ceramic Protective Coatings. Chapman \u0026amp; HaIl, London.https://doi.org/10.1007/978-94-009-1501-5\u003c/li\u003e\n\u003cli\u003eMaeda K., Yasuda K., Nohira T., Hagiwara R, Homma T.(2015) Silicon Electrodeposition in Water-soluble KF\u0026ndash;KCl Molten Salt: Investigations on the Reduction of Si(IV) Ions. J. Electrochem. Soc. 162(9): D444\u0026ndash;D448.https://doi.org/10.1149/2.0441509jes\u003c/li\u003e\n\u003cli\u003eLepinay J. De, Boutelion J., Traore S., Renaud D., and Barbier M.J. (1987) Electroplating silicon and titanium in molten fluoride Media. J. Appl. Electrochem\u003cem\u003e.\u003c/em\u003e 17: 294\u0026ndash;302.https://doi.org/10.1007/BF01023295\u003c/li\u003e\n\u003cli\u003eChen X., Liang Ch. (2019) Transition Metal Silicides: Fundamentals, Preparation and Catalytic Applications. Catal. Sci. Technol. 9: 4785\u0026ndash;4820.https://doi.org/10.1039/C9CY00533A\u003c/li\u003e\n\u003cli\u003eDownes N., Vasquez R., Maldonado S. (2022) Electroreduction of Si(NCO)\u003csub\u003e4\u003c/sub\u003e for Electrodeposition of Si. J. Electrochem. Soc. 169: 052509. https://doi.org/10.1149/1945-7111/ac5137\u003c/li\u003e\n\u003cli\u003eVivegnis S., Baudhuin L.-C., Delhalle J., Mekhalif Z., Renner F.U. (2024) Electrodeposition of silicon flms from organic solvents on nanoporous copper substrates. 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(2016) Diagnostic Criteria for Identifying an ECE Mechanism with Cyclic Square Wave Voltammetry. J. Electrochem. Soc. 63: H3101\u0026ndash;H3109. https://doi.org/10.1149/2.0151604jes\u003c/li\u003e\n\u003cli\u003eShoshani Y., Jerby E. (2022) Microwave-ignited DC-plasma ejection from basalt: Powder-generation and lightning-like effects. Appl. Phys. Lett. 120: 264101. https://doi.org/10.1063/5.0096020\u003c/li\u003e\n\u003cli\u003eJian L., Fang G., Li Zh., Kai X., Zhang D., Chen Zh., Humphries S., Heness G., Yeung W.Y. (2011) An approach to the uniform dispersion of a high volume fraction of carbon nanotubes in aluminum powder. Carbon. 49: 1965-1971. https://doi.org/10.1016/j.carbon.2011.01.021\u003c/li\u003e\n\u003cli\u003eGilmore C.J., Kaduk J.A., Schenk H. (2019)International Tables for Crystallography Volume H: Powder diffraction. Wiley. https://doi.org/10.1107/97809553602060000115\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Silicon, Electrochemistry, Ion-organic melts","lastPublishedDoi":"10.21203/rs.3.rs-5278871/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5278871/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe solubility of silicon oxides and fluorides in ionic-organic melts ((NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO, CH\u003csub\u003e3\u003c/sub\u003eCONH\u003csub\u003e2\u003c/sub\u003e and С\u003csub\u003e3\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eN\u003csub\u003e2\u003c/sub\u003e) has been studied. For electrochemical investigations, the system (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6 \u003c/sub\u003ewas chosen. Voltammetric studies showed that the most electropositive electrochemical process in the (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e melt is the discharge of ions of silicon in the oxidation state (IV) to silicon in the oxidation state (II) followed by the formation of elemental silicon. Micron coatings of silicon on Ni and stainless steel have been obtained by electrolysis of a (NH\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCO–(NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eSiF\u003csub\u003e6\u003c/sub\u003e melt at 120\u0026nbsp;\u003csup\u003e°\u003c/sup\u003eС.\u003c/p\u003e","manuscriptTitle":"Electrochemical Behavior of (NH2)2CO–(NH4)2SiF6 Melt","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-13 18:02:28","doi":"10.21203/rs.3.rs-5278871/v1","editorialEvents":[{"type":"communityComments","content":1}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"100c96f2-26d1-4650-8766-7c35b81392e1","owner":[],"postedDate":"December 13th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-28T15:24:02+00:00","versionOfRecord":[],"versionCreatedAt":"2024-12-13 18:02:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5278871","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5278871","identity":"rs-5278871","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}