Mechanisms of Lithium Intercalation and Conversion Processes in Organic–Inorganic Halide Perovskites

Organic–inorganic halide perovskites are attracting extraordinary attention in the field of energy materials. The reaction of hybrid lead halide perovskites with Li metal has recently been proposed for a number of potential applications. However, the mechanisms for Li uptake in such materials, such as intercalation and conversion, are still unknown. Using a combination of density functional theory and electrochemical and diffraction techniques, we consider Li intercalation and conversion reactions in CH3NH3PbI3, CH3NH3PbBr3, and CH3NH3PbCl3. Our simulations suggest that conversion reactions with Li are far more energetically preferable in these materials than Li intercalation. Calculations confirm the formation of Pb metal as a result of Li conversion in all three materials, and this is supported by X-ray diffraction analysis of CH3NH3PbBr3. The results of this study provide fresh insights into lithium and halide perovskite reactions that will hopefully drive further exploration of these materials for a wider variety of energy applications.