Microplastics and their effects on the environment and food chain have become increasingly important in recent years. These polymer particles, which are only few millimeters in size or smaller, accumulate in the environment and can enter the human food chain via animals that ingest them. Moreover, they can accumulate impurities such as heavy metals. Therefore, this study focuses on the indiffusion behavior of metal ions into semicrystalline polypropylene (PP) applying time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) at cryo‐conditions. Diffusion coefficients of Cu2+ and Ni2+ in PP are determined by classical SIMS depth profiling in frozen state (T <−130°C) and subsequent data analysis according to Fick's second law of diffusion. The results show that diffusion of Cu2+ ions in dry PP (DPP,Cu = [2.21 ± 0.15]·10−12 cm2/s) is faster compared to Ni2+ ion diffusion of dry PP (DPP,Ni = [4.43 ± 0.55]·10−13 cm2/s). Interestingly, the diffusion of Cu2+ ions in water‐saturated PP (DPP,H2O,Cu = [1.91 ± 0.28]·10−13 cm2/s) is slower compared to Cu2+ ion diffusion in dry PP. Furthermore, high‐lateral resolution ToF‐SIMS analysis shows that metal ions only diffuse in certain areas of PP, which are most likely amorphous.

In this study, radio-frequency sputtered tantalum vanadium oxide (TaVO x ) films are investigated as a promising material for the ion storage layer in an electrochromic device. Using spectroelectrochemical measurements by cyclic voltammetry, the electrochromic switching properties of the material are presented. The intercalation and deintercalation mechanisms of Li+ ions into TaVO x thin films have been studied by X-ray photoelectron spectroscopy. To obtain information about the composition and electronic structure of the material, films with different degrees of intercalation levels of Li+ ions are studied. The results clarify which species are involved in the electrochromic mechanism. In order to be able to evaluate the stability of electrochemically treated samples, films in the final deintercalated state are also analyzed. It is shown that only vanadium is actively involved in the investigated redox reaction. Finally, TaVO x is integrated with the solid-state electrolyte lithium phosphorus sulfuric oxynitride into a model electrochromic switching cell. Chronoamperometry shows a stable charge transfer of about 27 mC cm–2 combined with suitable values for optical transmittance of more than 70% (at 550 nm). Based on the high stability in terms of charge density and suitable color neutrality, we confirm the general suitability of this material combination for use in electrochromic applications.

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/admi.202202422.