37 research outputs found
Elaboration de micro-supercondensateurs à base d'électrodes en silicium nanostructuré : des nanomatériaux aux dispositifs
Since 1990, portable electronics is a thriving field. Devices gather more and more functions and thusrequire more and more efficient energy sources in terms of power, autonomy and lifespan. Such sourcesshould be fixed as close as possible from the micro-electronic circuit, ideally directly on chip. Microsupercapacitorsare a promising solution. Due to the electrodes materials (carbon or metallic oxide), theirfabrication directly on chip is still difficult. It should be easier with silicon based electrodes. The aim of thiswork is the elaboration of micro-supercapacitors with nanostructured silicon based electrodes. Theirperformances can be improved by working on the electrode and the electrolyte. The electrode must bestable in the electrolyte and have a high developed surface. The electrolyte must lead to high voltage. Thiswork demonstrates that only highly doped silicon electrodes with an adapted surface treatment have acapacitive behavior. The electrode surface can be increased via nanostructures growth of by gold-catalyzedCVD. Thanks to the study of the influence of growth parameters on the nanostructures morphology, theprocess has been optimized to get highly doped, dense, long and hyperbranched nano-trees with severalbranches generations. Their doping level is precisely monitored thanks to the use of HCl. Doping, length,density and branches are the key parameters to improve the electrode capacity. Micro-supercapacitorsperformances (maximum voltage, energy, power, stability) with such electrodes have been evaluated inseveral electrolytes. Higher voltage, and thus higher energy and power can be reached in ionic liquids.Several improvement trails are investigated: surface treatment, new device design. Our processcompatibility with micro-electronics one has been checked.Depuis les annĂ©es 1990, l'Ă©lectronique portable connait un vĂ©ritable essor. De plus en pluscomplexes, ces appareils requiĂšrent des besoins Ă©nergĂ©tiques croissants en termes de puissance,d'autonomie et de durĂ©e de vie. De nouveaux dispositifs de stockage pouvant ĂȘtre assemblĂ©s au plusproche du circuit micro-Ă©lectronique et dans l'idĂ©al directement sur la puce doivent donc ĂȘtre dĂ©veloppĂ©s.Les micro-supercondensateurs reprĂ©sentent une solution prometteuse. ConstituĂ©s principalementdâĂ©lectrodes en carbone ou oxydes mĂ©talliques, leur fabrication sur les puces de micro-Ă©lectroniques restedifficile. Cette intĂ©gration serait facilitĂ©e avec des Ă©lectrodes Ă base de silicium. Lâobjectif de cette thĂšse estl'Ă©laboration de micro-supercondensateurs constituĂ©s dâĂ©lectrodes en silicium nanostructurĂ©. Leursperformances peuvent ĂȘtre amĂ©liorĂ©es en travaillant Ă la fois sur les Ă©lectrodes et sur lâĂ©lectrolyte.LâĂ©lectrode doit ĂȘtre stable en prĂ©sence de lâĂ©lectrolyte et avoir une grande surface dĂ©veloppĂ©e.LâĂ©lectrolyte doit permettre dâatteindre une tension Ă©levĂ©e. Ce travail dĂ©montre que seules les Ă©lectrodes ensilicium fortement dopĂ©es avec un traitement de surface adaptĂ© ont un comportement capacitif. La surfacedes Ă©lectrodes est augmentĂ©e via la croissance de nanostructures par CVD catalysĂ©e par de lâor. LâĂ©tude delâinfluence des paramĂštres de croissance sur la morphologie des nanostructures a permis dâoptimiser leprocĂ©dĂ© pour obtenir des nano-arbres fortement dopĂ©s longs, denses, hyperbranchĂ©s et avec plusieursgĂ©nĂ©rations de branches ont pu ĂȘtre obtenus. Lâutilisation du chlorure dâhydrogĂšne permet de contrĂŽlerprĂ©cisĂ©ment le dopage des nanofils. Les paramĂštres clĂ©s des nanostructures pour obtenir de meilleurescapacitĂ©s ont Ă©tĂ© identifiĂ©s : dopage, longueur, densitĂ©, branches. Les performances des microsupercondensateurs(Tension maximale, Energie, Puissance, StabilitĂ©) avec des Ă©lectrodes en siliciumnanostructurĂ©e ont Ă©tĂ© Ă©valuĂ©es dans diffĂ©rents Ă©lectrolytes. Lâutilisation de liquide ionique (EMI-TFSI)permet dâaugmenter la tension maximale et donc lâĂ©nergie et la puissance. Des pistes dâamĂ©lioration ont Ă©tĂ©Ă©tudiĂ©es : traitement de surface, nouvelles architecture de dispositifs. La compatibilitĂ© des procĂ©dĂ©s utilisĂ©savec ceux de micro-Ă©lectronique a aussi Ă©tĂ© vĂ©rifiĂ©e
Ionic Liquid-Based Electrolytes for Supercapacitor and Supercapattery
There is a strong desire to replace or complement aqueous and organic electrolytes by ionic liquids (ILs) in electrochemical energy storage (EES) devices to achieve high operating voltages and hence high energy capacity. ILs are regarded as the inherent and competitive electrolytes since they were introduced to the electrochemical research community because they can overcome many disadvantages of the conventional aqueous and organic electrolytes, such as narrow potential windows, volatility, and flammability. This paper reviews critically the recent literatures of IL-based electrolytes used in supercapacitor, supercapattery, and micro-supercapacitor. Supercapattery is a generic term for various hybrid devices combining the merits of rechargeable battery and supercapacitor and often shows capacitive behavior. Fundamentals of supercapattery are briefly explained with typical examples. Micro-supercapacitor falls in the same scope of supercapacitor and supercapattery and shares the same fundamental concerns besides topology or structure. The future of IL-based electrolytes for the capacitive EES devices are also prospected
Elaboration of micro-supercapacitors with nanostructured silicon based electrodes : from materials to devices : from materials to devices
Depuis les annĂ©es 1990, l'Ă©lectronique portable connait un vĂ©ritable essor. De plus en pluscomplexes, ces appareils requiĂšrent des besoins Ă©nergĂ©tiques croissants en termes de puissance,d'autonomie et de durĂ©e de vie. De nouveaux dispositifs de stockage pouvant ĂȘtre assemblĂ©s au plusproche du circuit micro-Ă©lectronique et dans l'idĂ©al directement sur la puce doivent donc ĂȘtre dĂ©veloppĂ©s.Les micro-supercondensateurs reprĂ©sentent une solution prometteuse. ConstituĂ©s principalementdâĂ©lectrodes en carbone ou oxydes mĂ©talliques, leur fabrication sur les puces de micro-Ă©lectroniques restedifficile. Cette intĂ©gration serait facilitĂ©e avec des Ă©lectrodes Ă base de silicium. Lâobjectif de cette thĂšse estl'Ă©laboration de micro-supercondensateurs constituĂ©s dâĂ©lectrodes en silicium nanostructurĂ©. Leursperformances peuvent ĂȘtre amĂ©liorĂ©es en travaillant Ă la fois sur les Ă©lectrodes et sur lâĂ©lectrolyte.LâĂ©lectrode doit ĂȘtre stable en prĂ©sence de lâĂ©lectrolyte et avoir une grande surface dĂ©veloppĂ©e.LâĂ©lectrolyte doit permettre dâatteindre une tension Ă©levĂ©e. Ce travail dĂ©montre que seules les Ă©lectrodes ensilicium fortement dopĂ©es avec un traitement de surface adaptĂ© ont un comportement capacitif. La surfacedes Ă©lectrodes est augmentĂ©e via la croissance de nanostructures par CVD catalysĂ©e par de lâor. LâĂ©tude delâinfluence des paramĂštres de croissance sur la morphologie des nanostructures a permis dâoptimiser leprocĂ©dĂ© pour obtenir des nano-arbres fortement dopĂ©s longs, denses, hyperbranchĂ©s et avec plusieursgĂ©nĂ©rations de branches ont pu ĂȘtre obtenus. Lâutilisation du chlorure dâhydrogĂšne permet de contrĂŽlerprĂ©cisĂ©ment le dopage des nanofils. Les paramĂštres clĂ©s des nanostructures pour obtenir de meilleurescapacitĂ©s ont Ă©tĂ© identifiĂ©s : dopage, longueur, densitĂ©, branches. Les performances des microsupercondensateurs(Tension maximale, Energie, Puissance, StabilitĂ©) avec des Ă©lectrodes en siliciumnanostructurĂ©e ont Ă©tĂ© Ă©valuĂ©es dans diffĂ©rents Ă©lectrolytes. Lâutilisation de liquide ionique (EMI-TFSI)permet dâaugmenter la tension maximale et donc lâĂ©nergie et la puissance. Des pistes dâamĂ©lioration ont Ă©tĂ©Ă©tudiĂ©es : traitement de surface, nouvelles architecture de dispositifs. La compatibilitĂ© des procĂ©dĂ©s utilisĂ©savec ceux de micro-Ă©lectronique a aussi Ă©tĂ© vĂ©rifiĂ©e.Since 1990, portable electronics is a thriving field. Devices gather more and more functions and thusrequire more and more efficient energy sources in terms of power, autonomy and lifespan. Such sourcesshould be fixed as close as possible from the micro-electronic circuit, ideally directly on chip. Microsupercapacitorsare a promising solution. Due to the electrodes materials (carbon or metallic oxide), theirfabrication directly on chip is still difficult. It should be easier with silicon based electrodes. The aim of thiswork is the elaboration of micro-supercapacitors with nanostructured silicon based electrodes. Theirperformances can be improved by working on the electrode and the electrolyte. The electrode must bestable in the electrolyte and have a high developed surface. The electrolyte must lead to high voltage. Thiswork demonstrates that only highly doped silicon electrodes with an adapted surface treatment have acapacitive behavior. The electrode surface can be increased via nanostructures growth of by gold-catalyzedCVD. Thanks to the study of the influence of growth parameters on the nanostructures morphology, theprocess has been optimized to get highly doped, dense, long and hyperbranched nano-trees with severalbranches generations. Their doping level is precisely monitored thanks to the use of HCl. Doping, length,density and branches are the key parameters to improve the electrode capacity. Micro-supercapacitorsperformances (maximum voltage, energy, power, stability) with such electrodes have been evaluated inseveral electrolytes. Higher voltage, and thus higher energy and power can be reached in ionic liquids.Several improvement trails are investigated: surface treatment, new device design. Our processcompatibility with micro-electronics one has been checked
Elaboration de micro-supercondensateurs à base d'électrodes en silicium nanostructuré : des nanomatériaux aux dispositifs
Since 1990, portable electronics is a thriving field. Devices gather more and more functions and thusrequire more and more efficient energy sources in terms of power, autonomy and lifespan. Such sourcesshould be fixed as close as possible from the micro-electronic circuit, ideally directly on chip. Microsupercapacitorsare a promising solution. Due to the electrodes materials (carbon or metallic oxide), theirfabrication directly on chip is still difficult. It should be easier with silicon based electrodes. The aim of thiswork is the elaboration of micro-supercapacitors with nanostructured silicon based electrodes. Theirperformances can be improved by working on the electrode and the electrolyte. The electrode must bestable in the electrolyte and have a high developed surface. The electrolyte must lead to high voltage. Thiswork demonstrates that only highly doped silicon electrodes with an adapted surface treatment have acapacitive behavior. The electrode surface can be increased via nanostructures growth of by gold-catalyzedCVD. Thanks to the study of the influence of growth parameters on the nanostructures morphology, theprocess has been optimized to get highly doped, dense, long and hyperbranched nano-trees with severalbranches generations. Their doping level is precisely monitored thanks to the use of HCl. Doping, length,density and branches are the key parameters to improve the electrode capacity. Micro-supercapacitorsperformances (maximum voltage, energy, power, stability) with such electrodes have been evaluated inseveral electrolytes. Higher voltage, and thus higher energy and power can be reached in ionic liquids.Several improvement trails are investigated: surface treatment, new device design. Our processcompatibility with micro-electronics one has been checked.Depuis les annĂ©es 1990, l'Ă©lectronique portable connait un vĂ©ritable essor. De plus en pluscomplexes, ces appareils requiĂšrent des besoins Ă©nergĂ©tiques croissants en termes de puissance,d'autonomie et de durĂ©e de vie. De nouveaux dispositifs de stockage pouvant ĂȘtre assemblĂ©s au plusproche du circuit micro-Ă©lectronique et dans l'idĂ©al directement sur la puce doivent donc ĂȘtre dĂ©veloppĂ©s.Les micro-supercondensateurs reprĂ©sentent une solution prometteuse. ConstituĂ©s principalementdâĂ©lectrodes en carbone ou oxydes mĂ©talliques, leur fabrication sur les puces de micro-Ă©lectroniques restedifficile. Cette intĂ©gration serait facilitĂ©e avec des Ă©lectrodes Ă base de silicium. Lâobjectif de cette thĂšse estl'Ă©laboration de micro-supercondensateurs constituĂ©s dâĂ©lectrodes en silicium nanostructurĂ©. Leursperformances peuvent ĂȘtre amĂ©liorĂ©es en travaillant Ă la fois sur les Ă©lectrodes et sur lâĂ©lectrolyte.LâĂ©lectrode doit ĂȘtre stable en prĂ©sence de lâĂ©lectrolyte et avoir une grande surface dĂ©veloppĂ©e.LâĂ©lectrolyte doit permettre dâatteindre une tension Ă©levĂ©e. Ce travail dĂ©montre que seules les Ă©lectrodes ensilicium fortement dopĂ©es avec un traitement de surface adaptĂ© ont un comportement capacitif. La surfacedes Ă©lectrodes est augmentĂ©e via la croissance de nanostructures par CVD catalysĂ©e par de lâor. LâĂ©tude delâinfluence des paramĂštres de croissance sur la morphologie des nanostructures a permis dâoptimiser leprocĂ©dĂ© pour obtenir des nano-arbres fortement dopĂ©s longs, denses, hyperbranchĂ©s et avec plusieursgĂ©nĂ©rations de branches ont pu ĂȘtre obtenus. Lâutilisation du chlorure dâhydrogĂšne permet de contrĂŽlerprĂ©cisĂ©ment le dopage des nanofils. Les paramĂštres clĂ©s des nanostructures pour obtenir de meilleurescapacitĂ©s ont Ă©tĂ© identifiĂ©s : dopage, longueur, densitĂ©, branches. Les performances des microsupercondensateurs(Tension maximale, Energie, Puissance, StabilitĂ©) avec des Ă©lectrodes en siliciumnanostructurĂ©e ont Ă©tĂ© Ă©valuĂ©es dans diffĂ©rents Ă©lectrolytes. Lâutilisation de liquide ionique (EMI-TFSI)permet dâaugmenter la tension maximale et donc lâĂ©nergie et la puissance. Des pistes dâamĂ©lioration ont Ă©tĂ©Ă©tudiĂ©es : traitement de surface, nouvelles architecture de dispositifs. La compatibilitĂ© des procĂ©dĂ©s utilisĂ©savec ceux de micro-Ă©lectronique a aussi Ă©tĂ© vĂ©rifiĂ©e
Elaboration de micro-supercondensateurs à base d'électrodes en silicium nanostructuré (des nanomatériaux aux dispositifs)
Depuis les annĂ©es 1990, l'Ă©lectronique portable connait un vĂ©ritable essor. De plus en pluscomplexes, ces appareils requiĂšrent des besoins Ă©nergĂ©tiques croissants en termes de puissance,d'autonomie et de durĂ©e de vie. De nouveaux dispositifs de stockage pouvant ĂȘtre assemblĂ©s au plusproche du circuit micro-Ă©lectronique et dans l'idĂ©al directement sur la puce doivent donc ĂȘtre dĂ©veloppĂ©s.Les micro-supercondensateurs reprĂ©sentent une solution prometteuse. ConstituĂ©s principalementd Ă©lectrodes en carbone ou oxydes mĂ©talliques, leur fabrication sur les puces de micro-Ă©lectroniques restedifficile. Cette intĂ©gration serait facilitĂ©e avec des Ă©lectrodes Ă base de silicium. L objectif de cette thĂšse estl'Ă©laboration de micro-supercondensateurs constituĂ©s d Ă©lectrodes en silicium nanostructurĂ©. Leursperformances peuvent ĂȘtre amĂ©liorĂ©es en travaillant Ă la fois sur les Ă©lectrodes et sur l Ă©lectrolyte.L Ă©lectrode doit ĂȘtre stable en prĂ©sence de l Ă©lectrolyte et avoir une grande surface dĂ©veloppĂ©e.L Ă©lectrolyte doit permettre d atteindre une tension Ă©levĂ©e. Ce travail dĂ©montre que seules les Ă©lectrodes ensilicium fortement dopĂ©es avec un traitement de surface adaptĂ© ont un comportement capacitif. La surfacedes Ă©lectrodes est augmentĂ©e via la croissance de nanostructures par CVD catalysĂ©e par de l or. L Ă©tude del influence des paramĂštres de croissance sur la morphologie des nanostructures a permis d optimiser leprocĂ©dĂ© pour obtenir des nano-arbres fortement dopĂ©s longs, denses, hyperbranchĂ©s et avec plusieursgĂ©nĂ©rations de branches ont pu ĂȘtre obtenus. L utilisation du chlorure d hydrogĂšne permet de contrĂŽlerprĂ©cisĂ©ment le dopage des nanofils. Les paramĂštres clĂ©s des nanostructures pour obtenir de meilleurescapacitĂ©s ont Ă©tĂ© identifiĂ©s : dopage, longueur, densitĂ©, branches. Les performances des microsupercondensateurs(Tension maximale, Energie, Puissance, StabilitĂ©) avec des Ă©lectrodes en siliciumnanostructurĂ©e ont Ă©tĂ© Ă©valuĂ©es dans diffĂ©rents Ă©lectrolytes. L utilisation de liquide ionique (EMI-TFSI)permet d augmenter la tension maximale et donc l Ă©nergie et la puissance. Des pistes d amĂ©lioration ont Ă©tĂ©Ă©tudiĂ©es : traitement de surface, nouvelles architecture de dispositifs. La compatibilitĂ© des procĂ©dĂ©s utilisĂ©savec ceux de micro-Ă©lectronique a aussi Ă©tĂ© vĂ©rifiĂ©e.Since 1990, portable electronics is a thriving field. Devices gather more and more functions and thusrequire more and more efficient energy sources in terms of power, autonomy and lifespan. Such sourcesshould be fixed as close as possible from the micro-electronic circuit, ideally directly on chip. Microsupercapacitorsare a promising solution. Due to the electrodes materials (carbon or metallic oxide), theirfabrication directly on chip is still difficult. It should be easier with silicon based electrodes. The aim of thiswork is the elaboration of micro-supercapacitors with nanostructured silicon based electrodes. Theirperformances can be improved by working on the electrode and the electrolyte. The electrode must bestable in the electrolyte and have a high developed surface. The electrolyte must lead to high voltage. Thiswork demonstrates that only highly doped silicon electrodes with an adapted surface treatment have acapacitive behavior. The electrode surface can be increased via nanostructures growth of by gold-catalyzedCVD. Thanks to the study of the influence of growth parameters on the nanostructures morphology, theprocess has been optimized to get highly doped, dense, long and hyperbranched nano-trees with severalbranches generations. Their doping level is precisely monitored thanks to the use of HCl. Doping, length,density and branches are the key parameters to improve the electrode capacity. Micro-supercapacitorsperformances (maximum voltage, energy, power, stability) with such electrodes have been evaluated inseveral electrolytes. Higher voltage, and thus higher energy and power can be reached in ionic liquids.Several improvement trails are investigated: surface treatment, new device design. Our processcompatibility with micro-electronics one has been checked.SAVOIE-SCD - Bib.Ă©lectronique (730659901) / SudocGRENOBLE1/INP-Bib.Ă©lectronique (384210012) / SudocGRENOBLE2/3-Bib.Ă©lectronique (384219901) / SudocSudocFranceF
Micro-ultracapacitors with highly doped silicon nanowires electrodes
International audienceHighly n-doped silicon nanowires (SiNWs) with several lengths have been deposited via chemical vapor deposition on silicon substrate. These nanostructured silicon substrates have been used as electrodes to build symmetrical micro-ultracapacitors. These devices show a quasi-ideal capacitive behavior in organic electrolyte (1 M NEt4BF4 in propylene carbonate). Their capacitance increases with the length of SiNWs on the electrode and has been improved up to 10 ÎŒFcmâ2 by using 20 ÎŒm SiNWs, i.e., â10-fold bulk silicon capacitance. This device exhibits promising galvanostatic charge/discharge cycling stability with a maximum power density of 1.4 mW cmâ2