Regensburg 2022 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 8: Materials for Storage and Conversion of Energy
MM 8.3: Vortrag
Montag, 5. September 2022, 16:15–16:30, H46
Li diffusion in perovskite materials for battery applications — •Wei Wei1, Julian Gebhardt1,2, Daniel Urban2,3, and Christian Elsässer1,2,3 — 1Cluster of Excellence livMatS, University of Freiburg, Germany — 2Fraunhofer Institute for Mechanics of Materials IWM, Freiburg, Germany — 3Freiburg Materials Research Center (FMF), University of Freiburg, Germany
Metal halide perovskites are promising photovoltaic (PV) absorber materials, with the highest power conversion efficiency values currently exceeding 22%. Furthermore, unlike most of the traditional PV materials, hybrid perovskites have a strong ionic character. Therefore, these materials have recently been reported to have good ionic conductivity and lithium storage potential,[1] allowing in principle the combination of a solar cell and a Li-ion battery in a single device. Here, we investigate this possibility by a Li-CsPbI3 model system. By means of density-functional-theory calculations, we consider two scenarios: 1) Li in the rigid cubic perovskite structure, and 2) Li in the perovskite structure with flexible tilted bonds, which is the more realistic scenario at room temperature. The results of our simulations show that in the less symmetric structure the interstitial Li sites become nondegenerate and Li ions migrate along more complicated paths and have to overcome higher barriers than in the cubic structure. Nevertheless, diffusing Li ions have to overcome only moderate energy barriers of 0.16-0.33 eV, corroborating the potential use of metal-halide perovskites as Li-ion conducting PV materials.
[1] Zhen Li et al. Energy Environ. Sci.10 (2017) 1234