Fluctuation in oil price and the effect of global warming forced us to look for the replacement of this fossil fuel by advanced high energy density metal air batteries. To bring this advanced technology to commercialize market we need to have noble metals (such as Pt/C) and metal oxides (such as RuO2 and MnO2) as catalysts in cathode to facile the oxygen reduction reaction while discharging process and oxygen evolution reaction when recharging the battery. However, the replacement of these noble metal-based catalysts is due to often suffer from multiple disadvantages, including high cost, low selectivity, poor stability and detrimental environmental effects. We developed one dimensional LaCo1-xNixO3-δ perovskites by simple electrospinning approach. We show that the progressive replacement of Co by Ni in the LaCo0.97O3- δ perovskite structure greatly altered the OER electrocatalytic activity and the La(Co0.71Ni0.25)0.96O3-δ composition exhibited the lowest overpotential of 324 at 10 mAcm-2 in 0.1M KOH. Subsequently as prepared La(Co0.71Ni0.25)0.96O3-δ nanostructured was used as cathode catalyst for aqueous zinc-air battery, which delivers high capacity of 705 mAh.g-1zinc in primary zinc-air battery. The rechargeable battery discharges with low overpotential of 0.792 V and 0.696 V at low capacity mode (400 mAh.g-1 catalyst) and high capacity mode (2500 mAh.g-1catalyst), respectively, this value is much lower than LaCo0.97O3-δ nanotube catalyst and precious Pt/C catalyst. In the second part of thesis, we synthesized a thin film carbon coated SiO2 nanosphere by hydrothermal method and we utilized this material as cathode catalyst for lithium-air battery, it delivers a capacity of 18588 mAh.g-1 of catalyst material at high current density of 150 mAh.g-1, which is nearly twice the capacity of nitrogen doped carbon material at same current density, and for rechargeable battery it last for ten cycles at a cutoff capacity of 1000 mAh.g-1. Later to elucidate the working mechanism behind this metalloid oxide catalyst, we also reported the post mortem analysis of cathode material of lithium-oxygen battery. ⓒ 2016 DGIST
Table Of Contents
Chapter 1: Introduction 1-- 1.1.Forward 1-- 1.2.Status and complication of fuel cell technology 4-- 1.3.PEM fuel cell 5-- 1.4. Lithium-ion battery technology 7-- 1.5.Metal-air battery 9-- 1.6.Aqueous system 10-- 1.6.1.Zinc-air battery 10-- 1.6.2.Zinc metal anode 11-- 1.6.3.Electrolyte 11-- 1.6.4.Air cathode catalys 12-- 1.7.Non-aqueous system 13-- 1.7.1.Lithium-air battery 13-- Chapter 2: Air cathode catalyst for aqueous zinc-air battery 16-- 2.1. Literature survey 16-- 2.2 Scope of the work 19-- 2.3. Experimental section 20-- 2.3.1.Electrospinning approach 20-- 2.3.2.Chemicals required 20-- 2.3.3. Method 20-- 2.3.4.Sol-gel approach 21-- 2.3.5.Chemicals required 21-- 2.3.6.Method 21-- 2.4. Material characterization 23-- 2.5. Electrochemical characterization 23-- 2.5.1.Electrochemical setup 23-- 2.5.2.Electrochemical active surface area 24-- 2.6.Zinc-air battery setup 25-- 2.7.Results and Discussion 27-- 2.7.1.Structural characterization 27-- 2.7.2.Electrochemical studies 40-- 2.7.3.Zinc-air battery performance 51-- 2.8.Summary 60-- Chapter 3: Nitrogen doped carbon coated SiO2 as air cathode catalyst for non-aqueous lithium-oxygen battery 61-- 3.1.Literature survey 61-- 3.2.Scope of the work 63-- 3.3.Experimental section 63-- 3.3.1.Hydrothermal approach 63-- 3.3.2.Chemicals Required 64-- 3.3.3.Synthesis procedure of SiO2 nanosphere 65-- 3.3.4.Synthesis procedure of SiO2/NC nanosphere 65-- 3.4.Material characterization 65-- 3.5.Electrochemical characterization 66-- 3.5.1.Electrochemical setup 66-- 3.6.Lithium oxygen cell assembly and testing 67-- 3.6.1.Air cathode preparation 67-- 3.7.Results and discussion 69-- 3.7.1.Structural analysis 69-- 3.7.2.Electrochemical studies 73-- 3.7.3.Lithium-oxygen battery performance 76-- 3.8. Summary 83-- Conclusions 84-- Reference 86-- Acknowledgement 105
Research Interests
Electrocatalysts for fuel cells; water splitting; metal-air batteries; Polymer electrolyte membranes for fuel cells; flow batteries; Hydrogen generation and utilization