Microwave Processing of Lithium Aluminium Germanium Phosphate Glass-Ceramics

Microwave (MW) processing of materials is a unique technology that provides a powerful and significantly different tool to process materials and in most cases improves the properties and the performance of materials. Materials processing using MW technology have several advantages when compared to the already known traditional materials processing techniques. These anticipated benefits include more precise volumetric heating, faster ramp-up to high temperature, lower energy consumption, and enhanced properties of the processed materials[1, 2]. On the other hand, safe and efficient energy storage systems are urgently needed in order to develop the future electricity systems that are based on low-carbon emissions renewable energy sources such as wind and solar sources. Li-ion batteries are unique storage systems that possess high energy densities and no memory effect features[3, 4]. The currently used liquid and/or polymer electrolytes have some safety risks such as inflammation and decomposition[5, 6]. Solid state electrolytes made of ion conducting glass-ceramics are thermally and mechanically more stable. It is expected that they will replace the current state of the art commercially used liquid and polymer electrolytes in the near future and consequently batteries would become much safer. Lithium aluminium germanium phosphate (LAGP) glass system with the chemical composition Li1.5Al0.5Ge1.5(PO4)3 is considered as one of the promising solid state electrolyte for Li-ion batteries. It was reported that the highest ionic conductivity value of LAGP was achieved when the specific ion conducting crystal phase with its specific microstructure was developed at the optimum crystallization temperature using several hours of conventional heat-treatment method[7, 8]. The goals of this project are to investigate the possibility of using MW energy for the processing of LAGP glass-ceramics. The effect of microwaves on the crystallization behavior of LAGP will be investigated. It is of great interest to investigate the effect of MW energy on the developed microstructure, on the ionic conductivity and on the activation energy of these MW heat-treated LAGP glass-ceramics compared to the conventional used method. If the optimum heat-treatment temperature and time that are required to achieve the highest ionic conductivity could be decreased and/or lowered when using MW processing compared to the used longer conventional method, this could results in a considerable amount of energy saving during its commercial production process. There is also a possibility of achieving higher ionic conductivity values of the MW treated samples since in many cases microwaves enhance the materials properties which consequently will enhance the whole battery capabilities and performance