Study on the hydrogen storage properties of NaAlH4 composites using taguchi method / Zarina Omar

Hydrogen is the perfect energy carrier for future transport, such as automotive applications. Hydrogen has attracted a great deal of interest among researchers as an ideal energy carrier used as a medium for transport and energy storage. In this study, the Taguchi Method is chosen as an effective statistical approach for analysing optimum factors and response in the selection of improved hydrogen storage properties of NaAlH4. One of the most useful solid hydrogen storage materials is NaAlH4. Researchers have widely studied complex metal hydride composites in the form of ABH4, where A is an alkali metal and B is a group III element, previously in solution as proton acceptors to increase H2 adsorption abilities. In this study, two factors, namely materials and catalysts, were considered for the optimum condition of onset decomposition temperature, activation energy, and hydrogen release, and whether the factors were important or negligible. Data were analysed using the ratio of signal to noise (S/N) and the variance of analysis (ANOVA). Secondary data from previous research were used to analyse using the Taguchi method. The ANOVA analysis results show that catalyst shows significant effect for the decomposition of temperature and activation energy. In the other hand, material show it is insignificant for all the parameters. Based on the "smaller the better" reaction of the decomposition temperature, the optimum amount and factors for the overall S/N ratio are NaAlH4_LiBH4 without catalyst at 125°C. In the case of hydrogen release, the "larger the better" the optimum conditions are the NaAlH4_LiBH4 material with NbF5 catalyst at 8wt. %. In the meantime, the NaAlH2_MgH2 material is the best criterion for activation energy which, is "smaller, the better" for optimum conditions without a catalyst at 54.3kJ/mol. The signal-to-noise ratio study showed that the catalyst had the most important effect on the control parameters tested. Therefore, the Taguchi method can be an excellent technique for enhancing the potential preparation of selective materials and catalysts for hydrogen storage.