Abstract
Thesis starts with the introduction and literature review of energy storage and conversion devices, which lay the background for motivation and purpose of this research. The fundamental background behind this work was laid by Zheng et al in 1995 [1], wherein they proposed a new charge storage mechanism of hydrous form of ruthenium oxide (i.e. RuO2.xH2O). They proposed this material as a prospective material for super capacitors and direct methanol fuel cells (DMFCs). Later, Wang et al proposed a monolithic hybrid direct methanol fuel cell, employing a layer of RuO2.xH2O between anode catalyst and membrane [3]. In the same paper, they discussed the probability of RuO2.xH2O supported Pt anode catalyst material. The first section of this work, which is covered in chapter 3, comprises of fundamental research and involves proposing and developing an electrode catalyst material for DMFC. It explains the heuristic approach, leading towards the methodical approach - which finally leads to the development of a catalyst material which, in addition to its remarkable feature of possessing high specific capacitance, could be compared with commercially available materials. The same section also covers the extensive study, testing and electrochemical results of this catalyst material, which included cyclic voltammetery, TEM, XRD and EDAX tests and results. The later segment of this work covers the application of this catalyst material in DMFC. Results from the same show that there is a significant improvement in dynamic response of the DMFC prepared using the proposed catalyst material, when compared to the one prepared using commercial catalyst. Steady state response, on the other hand is slightly degraded. It is discussed as what could be the probable reasons behind the reduced steady state response of the monolithic hybrid DMFC prepared using the new proposed catalyst material. High charge transfer resistance, poor mass transfer, poor dispersion and poor porosity could be few of the reasons behind reduced steady state performance of DMFC. Finally, we conclude that since the improved dynamic response of DMFC is evident using this catalyst material, combined with the fact that it exhibits excellent electrochemical surface area, good methanol oxidation activity, high specific capacitance and small particle size - one could very well extend this research in dealing with the aforementioned short comings. The necessity to extend this research could be estimated from the fact that once commercially realized, DMFCs could easily replace chargeable batteries in automobiles (and other applications). Unlike batteries, which are energy storage devices, DMFCs are energy conversion devices which run directly on fuel (methanol) and don’t be to be re-charged. Few of the issues which are hindering the commercialization of DMFCs are its low power density (poor energy density and poor dynamic response) and size. The catalyst material developed in this research is easy to synthesize in laboratory and promises to improve the dynamic response of DMFC, eliminating the need of an external battery or super capacitor for instantaneous power demands – hence, reducing its size and weight.
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