Polyaniline-coated Nanoporous Carbon Scaffold for Energy Storage and Water Deionization Applications

dc.contributor.advisorPonnurangam, Sathish
dc.contributor.advisorBirss, Viola I.
dc.contributor.authorAi, Chengying
dc.contributor.committeememberRoberts, Edward P. L.
dc.contributor.committeememberBenneker, Anne M.
dc.date2019-11
dc.date.accessioned2019-09-25T17:43:27Z
dc.date.available2019-09-25T17:43:27Z
dc.date.issued2019-09-20
dc.description.abstractThe world’s rapidly growing population urgently calls for more clean water. However, current water treatment technologies, e.g., reverse osmosis and distillation, are very energy demanding. Capacitive deionization (CDI) has emerged as a promising new technology for the production of clean water from brackish or even seawater at a high efficiency and at low cost, also showing promise in storing energy while simultaneously achieving desalination. In this work, a novel nanoporous carbon scaffold (NCS), a binder-free, free-standing, and 100% carbon film with a highly tunable nanoporous structure, has shown excellent promise as a CDI electrode. However, its surface area of 200-400 m2/g for the 50 and 85 nm diameter pore-sized NCS materials, limits the obtainable double layer capacitance. To further increase the electrochemical capacitance of the NCS material, polyaniline (PANi), a conducting polymer with a very high electrochemical capacitance (~750 F/g), was deposited on the NCS using cyclic voltammetry (CV), resulting in a PANi/NCS composite. A range of conformal PANi layers of controllable thicknesses were obtained, without blocking the pores of the NCS, as observed by scanning electron microscopy (SEM). The conformal PANi coating is uniform throughout the thickness of the NCS, as seen from SEM and energy-dispersive X-ray spectroscopy element mapping. Both CV and galvanostatic charge/discharge (GCD) methods were used to demonstrate the capacitive behavior of the PANi/NCS composite, with the capacitance increasing by 5 to 20 times of that obtained from the original NCS, thus possessing an excellent energy and power density. The PANi-coated NCS also demonstrates good cyclic stability, retaining ca. 85% of its original capacitance after 1000 GCD cycles. Electrochemical impedance spectroscopy (EIS) confirmed that the time constant of the PANi/NCS composites decreased with an increase in the PANi thickness, from 3 to 20 nm. A flow-through CDI test was carried out using three different cell configurations, including a symmetric NCS cell, a symmetric PANi/NCS cell and an asymmetric cell containing a PANi/NCS anode and an NCS cathode. When using the asymmetric CDI configuration, the salt adsorption capacity was 2.6 mg/g (0.019 mg/m2), while the salt adsorption can be completed very rapidly in only 2-10 seconds.en_US
dc.identifier.citationAi, C. (2019). Polyaniline-coated Nanoporous Carbon Scaffold for Energy Storage and Water Deionization Applications (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/37129
dc.identifier.urihttp://hdl.handle.net/1880/111067
dc.language.isoengen_US
dc.publisher.facultySchulich School of Engineeringen_US
dc.publisher.institutionUniversity of Calgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.en_US
dc.subjectElectrochemistryen_US
dc.subjectCapacitive deionizationen_US
dc.subjectNanoporous carbon scaffolden_US
dc.subjectConformal polyaniline coatingen_US
dc.subject.classificationEnergyen_US
dc.subject.classificationEngineering--Chemicalen_US
dc.subject.classificationEngineering--Environmentalen_US
dc.subject.classificationMaterials Scienceen_US
dc.titlePolyaniline-coated Nanoporous Carbon Scaffold for Energy Storage and Water Deionization Applicationsen_US
dc.typemaster thesisen_US
thesis.degree.disciplineEngineering – Chemical & Petroleumen_US
thesis.degree.grantorUniversity of Calgaryen_US
thesis.degree.nameMaster of Science (MSc)en_US
ucalgary.item.requestcopytrueen_US
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