Atom probe tomography characterisation of the solid-electrolyte interphase in lithium metal batteries

Metallic lithium is the ultimate negative electrode because of its high theoretical capacity and low negative potential. Lithium-metal anode batteries show great potential to meet the stringent energy density requirements for the future of electric flight. However, the inhomogeneous lithium plating on charge results in active lithium loss that severely limits cycle life and compromises safety. Ultimately lithium’s cycling performance is controlled by the solid electrolyte interphase (SEI), a thin (few nanometers) film formed by the reduction of the electrolyte in contact with metallic lithium. The properties of the SEI are directly related to its structure and composition and therefore an accurate structural characterisation is vital. The project aims to characterise the SEI by Atom Probe Tomography (APT), the only material analysis technique capable to probe both 3D imaging and chemical composition at the atomic scale.