Ordered mesoporous carbon (OMC) is a versatile material providing interconnected channels for the diffusion of electroactive species in electrochemical systems.

Researchers have debated whether methylammonium lead iodide (MAPbI₃), with a perovskite crystal structure, is ferroelectric and therefore contributes to the current–voltage hysteresis commonly observed in hybrid perovskite solar cells (PSCs). We thoroughly investigated temperature-dependent polarization, dielectric, and impedance spectroscopies, and we found no evidence of ferroelectric effect in a MAPbI₃ thin film at normal operating conditions. Therefore, the effect does not contribute to the hysteresis in PSCs, whereas the large component of ionic migration observed may play a critical role. Our temperature-based polarization and dielectric studies find that MAPbI₃ exhibits different electrical behaviors below and above ca. 45 °C, suggesting a phase transition around this temperature. In particular, we report the activation energies of ionic migration for the two phases and temperature-dependent permittivity of MAPbI₃. This study contributes to the understanding of the material properties and device performance of hybrid perovskites.

An hierarchical porous carbon nanostructure with intrinsic O- and N-dopants and an ultrahigh specific surface area of 1500 m² g⁻¹ is reported towards the goal of designing and achieving a better sulfur electrode for lithium–sulfur batteries (LSBs) that can provide both large sulfur loading and large sulfur content and are based on a facile fabrication process. This nanostructure was derived from crude soybeans in a facile pyrolysis process. Using it as a sulfur host, the S/C active composite with 80% sulfur content was made. Cells with different sulfur loadings were investigated and were found to demonstrate large capacity, high coulombic and energy efficiencies, and high cycling stability. In particular, for a sulfur loading of 5.5 mg cm⁻² and a sulfur content of 80%, cells displayed a specific capacity of ca. 950 mA h g⁻¹, which corresponds to an areal capacity of 5.2 mA h cm⁻². Such a performance moves LSB technology closer to practical applications.