Bond-valence based computational design of high performance lithium ion battery cathode materials

Abstract

Linking the bond valence mismatch to the absolute energy scale, a generally applicable Morse-type force-field is developed and applied to study ion conduction in mixed conducting solids using both an energy landscape approach and molecular dynamics (MD) simulations. Exploring strategies to enhance the power performance of safe low cost lithium ion battery cathode materials, amblygonite-type "high voltage" cathode materials LiVPO 4F and LiFeSO 4F are used as examples. The amblygonite-type structure exhibits channels for low-energy migration in combination with moderate energy thresholds for "back-up" pathways in perpendicular directions mitigating the effects of channel blocking in mixed conductors with strictly one-dimensional Li + motion. © 2011 Materials Research Society.