Alkali Metal Based Micro Combustion Using Graphene Micro-valve Trigger

Abstract

Controllable combustion of alkali metals offers a pathway to high energy density, high power density scalable thermal systems. The volatile nature of these materials however, has limited their incorporation into useable devices. Recent findings in low trigger power MEMS one-shot valves offer a viable pathway forward for creating systems in which to exploit the unique properties of alkali metals as thermal energy sources. By miniaturizing and combining these fuels with such a valve, and incorporating them with a polymer substrate, a micro-packet of combustible metal can be created. Here we report such a device utilizing a graphene based micro-valve trigger and a rubidium metal fuel source to realize an arrayable micro-scale electrical to thermal energy amplification scheme. Using this approach we can react nanoliter droplets of rubidium with ambient air on demand, producing electrical to thermal energy gains of seventy five times. By arraying the fuel into discrete packets, we can also achieve temporal control of the fuel source, allowing for tailored peak and average power output.