Gillian Hawes1 Michael Pope1

1, University of Waterloo, Waterloo, Ontario, Canada

The lithium-ion battery is the rechargeable power source for nearly all modern portable electronics and electric vehicles, due to its relatively high energy density, negligible memory effect, and minute self-discharge. Despite its widespread use in modern electronics, the drive for a sustainable energy future and applications such as all-electric vehicles, robots, and drones require future batteries to possess much higher energy densities. A major limitation faced by lithium-ion batteries stems from the graphite anode, commonly used due to its stability upon lithiation, which possesses a relatively low capacity compared to next-generation anode materials such as lithium, silicon and lithium alloy materials. Switching to these materials could significantly boost the energy density of lithium-ion batteries and would also enable high capacity next-generation chemistries beyond lithium-ion. Lithium metal in particular is considered the ideal anode material, as it possesses the lowest electrochemical potential and an extremely high theoretical capacity. Still, the implementation of lithium metal anodes is currently impeded by their significant volume change upon charging and discharging, lithium metal’s propensity to grow dendritic structures that can cause dangerous short circuits, and the instability of the solid electrolyte interface that forms upon exposing the anode to electrolyte. Unique nanomaterials can provide a key advancement in the development of high capacity lithium anodes by controlling the transport and storage of ions at the nanoscale. In this work, we investigate several non-porous carbon-based thin films that can act as selectively-permeable lithium-ion membranes and as protective intermediaries between the lithium metal anode and the electrolyte. These coatings serve to block electrolyte, form a stable solid electrolyte interface, and limit the formation of dendrites. We demonstrate the performance of the protected lithium metal anodes in symmetric lithium-lithium cells and in lithium-sulfur batteries, signifying the ability of these protection layers to provide a key step towards safe and highly energy-dense next-generation rechargeable batteries.