Synthesis, preparation and characterisation of materials for metal air battery applications

Examensarbete för masterexamen
Master Thesis
Applied physics (MPAPP), MSc
Bergman, Martin
Energy is one of the most important commodities today, as we use it in almost every aspect of our lives. The need to be able to store energy has increased dramatically the last couple of decades, and with the emergence of electric vehicles and increased use of intermittent energy sources this need shows no sign of diminishing. One way of storing energy is the use of batteries. There are many different types of batteries but one type that has started to receive increased attention lately is the metal-air battery, using oxygen from the atmosphere as one of the electrodes, allowing more of the other electrode to take up the space inside the battery and thereby increasing the capacity both per weight and volume. One of the most promising metals for this use is zinc, which is cheap, abundant and environmentally benign. However, there are problems during recharge of zinc-air batteries, most importantly the formation of so called dendrites, which are structures of zinc that can short circuit the battery. In this report, one method to subdue this dendrite formation is investigated. The idea is that by applying a film over the electrode the zinc deposition will be more even and dendrite formation will not occur. It has earlier been proven that this concept works with a zeolite film, and this report will cover two parts: 1. Investigate how the impedance of the zeolite film depend on its thickness and 2. Investigate if the concept works with either sol-gel or silica gel films. To further increase the efficiency, experiments were made to functionalize the film so that it acted as a molecular sieve to capture the dissolved zinc ions upon release from the electrode so that they stayed in the vicinity of the electrode. The results show that the impedance does depend on the zeolite layer thickness, and the alternative methods with sol-gel and silica gel are promising and show proof of concept, giving an increase in efficiency. It was also proven through FTIR measurements that the functionalization worked, but a good preparation method is needed in order to make thorough experiments.
Fysik , Physical Sciences
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