The structural and pyroelectric properties of partially Ca‐substituted BaTiO3, Ba1−xCaxTiO3 (0 ≤ x ≤ 0.2), are investigated. Partial Ca‐substitution in BaTiO3 introduced tetragonal distortion in the TiO6 octahedrons and increased the displacement, Δd, of a Ti4+ cation from the center of an octahedron. This increase in Δd led to enhancement of remanent polarization and pyroelectric voltage, Vp. The pyroelectric energy storage behavior is demonstrated for the partially Ca‐substituted BaTiO3. For the Ba0.9Ca0.1TiO3 sample which exhibited the highest Vp, the stored energy in an output capacitor was proven to be sufficient to operate micropower Internet of Things devices.

Pyroelectric Energy Harvesting Suppose that electricity can be generated from enormous amount of waste heat, then an avenue to solve energy and environmental problems is provided. When heatingcooling cycles are applied to a ferroelectric material, pyroelectric current is generated and electric charge can be stored in a capacitor. Here, the results of crystal structure, polarization, pyroelectric voltage, and energy storaging tests of Ca‐substituted BaTiO3 are presented. The Ca substitution enhances the polarization in BaTiO3 due to the introduction of further tetragonal distortion in the TiO6 octahedrons. Consequently, a higher pyroelectric voltage is achieved compared with BaTiO3, which enables the authors to store 4.2 μJ in the capacitor after four heating‐cooling cycles between 304 and 332 K. The results demonstrate that Pb‐free, i.e., ecofriendly ferroelectric materials such as BaTiO3 have a potential for the pyroelectric energy harvesting. This is reported by Kei Hayashi and co‐workers in article number http://doi.wiley.com/10.1002/pssa.201701002.