Multifunctional properties and multi-energy storage in the [(CH3)3S][FeCl4] plastic crystal

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 °C (315 K) and 29 °C (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 permittivity 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 the coexistence of multifunctional properties that can be useful for both solar thermal and electric energy storage.