University of Freiburg researchers have evaluated how suitable halide-perovskites are for advanced photoelectrochemical battery applications. The recent paper unveiled important findings that could influence the use of organic-inorganic perovskites as multifunctional materials in integrated photoelectrochemical energy harvesting and storage devices.
Importantly, the research has revealed the tendency for 2-(1-cyclohexenyl)ethyl ammonium lead iodide (CHPI) perovskites to dissolve in highly polar electrolytes commonly employed in current lithium-ion batteries. The selection of low polarity electrolytes stabilizes the CHPI electrode material, leading to purely capacitive behaviors in batteries and minimizing lithium-ion intercalation. However, when applying a galvanostatic charge whilst the perovskite electrode material is in contact with electrolyte leads to photo corrosion and CHPI phase dissolution.
Moreover, oxidative corrosion can also be induced by illuminating the material without the use of external voltage or oxidizing the material in dark conditions. Faradic plateaus are produced by the dissolved species, but the authors have noted that these plateaus do not necessarily indicate lithium-ion intercalation in the solid CHPI phase or correspond to photo-assisted charge.
According to the researchers, halide perovskites are not suitable for use in mode III photo battery systems. These materials possess inherent photochemical, chemical, and electrical instability and, furthermore, are incompatible with lithium-ion-based intercalation chemistry. They are unsuitable for use with polar electrolytes, which are commonly used in current lithium-ion batteries.
Some of the currently reported perovskites may be suitable as anode conversion type electrodes, but the results of studies on this use of these materials are not applicable to multifunctional photo battery cathode material research.
Overall, the new paper has provided fascinating experimental analysis and characterization of organic-inorganic halide perovskites in photoelectrochemical systems. While the study’s findings indicate that the material may not be suitable for integrated systems, it will help to inform future research on improved materials for this key technological application.
