2, University of Strathclyde, Glasgow, , United Kingdom
Perovskites are versatile structures with an impressive range of applications due to their exotic physical properties including ferroelectric, dielectric, pyroelectric, and piezoelectric behaviors. This versatility is due to their robust framework, which allows multiple combinations of different cations and anions in the structure. Despite this, the use of perovskites in lithium-ion batteries has been very limited with only a few reports existing such as lithium lanthanum titanate as a fast lithium conductor and lithium lanthanum niobate as an insertion electrode. Introduction of a second cation on the B-site can produce complex structures containing two different B-site cations, and if these two cations on the B-site order along the crystal then the lattice parameter doubles in size giving rise to a so-called double perovskite structure. Here I will present our latest findings on a series of lithium-rich double perovskites as a new class of materials for all solid state lithium ion batteries, which display excellent stability and electrochemical performance. The perovskite structure is famously amenable to chemical and structural adjustment and by taking advantage of this we propose a new class of perovskite lithium cathode materials. I will present our comprehensive study of these materials using X-ray and neutron diffraction, total scattering, X-ray absorption analysis, impedance spectroscopy, muon spin relaxation measurements and their electrochemical evaluation in lithium ion battery cells. I will show that the combination of lithium mobility along with a redox active metal in a high oxidation state allows electrochemical deintercalation of lithium to provide a new class of electrode materials for lithium batteries.