Analysis and development of selective synthesis methods of hierarchical micro- and mesoporous carbons
Date
2019-07-08
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Abstract
Loodussäästlikule ning jätkusuutlikule energeetikale pööratakse kogu maailmas järjest enam tähelepanu võitlemaks globaalsete kliimaprobleemidega. Selleks, et taastuvaid energiaallikaid kasutada, on vajalikud ka efektiivsed energiasalvestussüsteemid. Üheks neist on superkondensaatorid, mis võimaldavad väga kiiret laadimist ja tühjendamist ning samas sobivad suurt võimsust nõudvate rakenduste korral. Üheks väga oluliseks superkondensaatorite töövõimet mõjutavaks elemendiks on kasutatav elektroodi materjal. Erinevad poorsed süsinikmaterjalid on selleks rakenduseks väga levinud. Poorsete süsinikmaterjalide alane teadustöö ning ka nende tootmine ja kasutamine maailmas aina kasvab. Lisaks energiasalvestusseadmetele kasutatakse neid ka näiteks veepuhastusseadmetes, vesiniku salvestamiseks jne.
Sõltuvalt rakendusest peavad süsinikmaterjalid olema selleks vajalike omaduste ja struktuuriga, mis omakorda sõltuvad väga oluliselt antud süsinikmaterjalide sünteesi meetodist. Lähteaineks võivad olla näiteks suhkur, biomass, karbiidid, polümeerid jne. Selleks, et materjalid oleksid ka reaalselt erinevates rakendustes kasutatavad, on väga oluline hinna ja kvaliteedi suhe – otsitakse materjale, mida oleks võimalikult lihtne ja odav valmistada, kuid samas oma parameetritelt oleksid rakenduste jaoks sobivad.
Käesoleva doktoritöö raames valmistati poorseid süsinikmaterjale ränikarbiidist ning uuriti erinevate järeltöötluse meetodite mõju saadud materjalide füüsikalistele omadustele (poorsus, korrapära ja struktuur). Seejärel valmistati uuritud materjalidest superkondensaatori elektroodid ja testiti mitmekülgselt ka nende sobivust kasutamiseks energiasalvestusseadmetes. Töö tulemused näitavad, et ränikarbiid, mis on teistest sarnastest kasutatavatest karbiididest 10 kuni 60 korda odavam, on väga lihtsa ning küllaltki odava sünteesi ja järeltöötluse meetodite abil võimalik töödelda efektiivseks materjaliks energiasalvestusseadmetes kasutamiseks.
Sustainable and eco-friendly energy is increasingly being given worldwide attention to tackle the global climate challenges. The application of renewable energy sources needs effective energy storage systems. One of these are supercapacitors, which allow very fast charging and discharging and at the same time are suitable for high power applications. One very important component affecting the performance of the supercapacitors are the active materials used for preparing the electrodes. Different porous carbon materials are very common for this application. Research, production and use of porous carbons is growing worldwide and in addition to energy storage devices, they are also widely used for example in water purification equipment, hydrogen storage, air purification, etc. Depending on the application, the carbon material must have specific properties and structure. These in turn depend on precursors and methods used to synthesize the carbon materials. Different precursors can be used, for example biomass, sugars, carbides, polymers, etc. The price-quality ratio must also be kept in mind – the material should be cheap and easy to produce, but suitable for the specific application. In this thesis, porous carbon materials were synthesized from silicon carbide and various post-treatment methods were studied to analyze their effect on the resulting materials properties (porosity, structure). Subsequently, these carbon materials and their suitability for application in high energy and power energy storage devices were tested. The results showed, that silicon carbide, which is 10 to 60 times cheaper than other similar carbides used, can be processed by simple and relatively inexpensive synthesis methods into a suitable and efficient material for energy storage devices.
Sustainable and eco-friendly energy is increasingly being given worldwide attention to tackle the global climate challenges. The application of renewable energy sources needs effective energy storage systems. One of these are supercapacitors, which allow very fast charging and discharging and at the same time are suitable for high power applications. One very important component affecting the performance of the supercapacitors are the active materials used for preparing the electrodes. Different porous carbon materials are very common for this application. Research, production and use of porous carbons is growing worldwide and in addition to energy storage devices, they are also widely used for example in water purification equipment, hydrogen storage, air purification, etc. Depending on the application, the carbon material must have specific properties and structure. These in turn depend on precursors and methods used to synthesize the carbon materials. Different precursors can be used, for example biomass, sugars, carbides, polymers, etc. The price-quality ratio must also be kept in mind – the material should be cheap and easy to produce, but suitable for the specific application. In this thesis, porous carbon materials were synthesized from silicon carbide and various post-treatment methods were studied to analyze their effect on the resulting materials properties (porosity, structure). Subsequently, these carbon materials and their suitability for application in high energy and power energy storage devices were tested. The results showed, that silicon carbide, which is 10 to 60 times cheaper than other similar carbides used, can be processed by simple and relatively inexpensive synthesis methods into a suitable and efficient material for energy storage devices.
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
ränikarbiid, süsinikmaterjalid, keemiline süntees, aktiveerimine, füüsikalised omadused, energiasalvestus, süntees