Multifunctional [(CH₃)₃S][FeCl4] Plastic Crystal for Solar Thermal and Electric Energy Storage

In this work, we report a new halometallate [(CH3)3S][FeCl4] with plastic crystal behaviour as a new material for multi-energy storage. This material undergoes a first-order solid-solid plastic crystal phase transition near room temperature with a relatively large latent heat (~40 kJ kg-1) and an operational temperature for storing and releasing thermal energy between 42 oC (315 K) and 29 oC (302 K), very appropriate for solar thermal energy storage. In addition, the dielectric, magnetization and electron spin resonance studies reveal that this material exhibits multifunctional properties with temperature-induced reversible changes in its dielectric, conducting and magnetic behaviour associated with the phase transition. Also, the dielectric permitivity increases sharply up to 5 times when inducing the phase transition, which can be exploited to store electric energy into a capacitor. Therefore, [(CH3)3S][FeCl4] is a very interesting compound with coexistence of multifunctional properties that can be useful for both solar thermal and electric energy storage.