Whilst rechargeable batteries continue to take over the consumer electronics market, they are unsuitable to replace specific battery technologies, such as the thermal battery, which can be used as an emergency power supply in aircraft. To date, existing thermal batteries use Li as the mobile ion. However, our recent work has focussed on batteries which use alternative mobile ions (which offer advantages over Li) and good electrochemical performances have been obtained. However, the evolution of the crystalline phases at the high operating temperature is unknown. Therefore we propose to carry out a combined in-situ diffraction and battery discharge experiment using the St Andrews Conductivity rig. This will contribute significantly to the thesis of a final year PhD student and will enable the structure-property relationships to be understood in these batteries.