Direct observation of an 80 K colossal barocaloric temperature change in one cycle of pressure application and release

Solid refrigerants are one of the candidate materials for future cooling technologies aimed at suppressing global warming. Among them, barocaloric solid refrigerants are drawing attention owing to their high caloric performance. Herein, we report a colossal barocaloric effect in the rubidium cyano-bridged zinc–manganese–iron material, RbZn _0.08 Mn _0.92 [Fe(CN) ₆ ] ( cyano-RbZnMnFe ). Direct measurements using a thermocouple revealed a temperature increase (∆ T _obs,increase ) of +46 K upon pressure application and a temperature decrease (∆ T _obs,decrease ) of −34 K by pressure release. The total temperature change in one cycle (∆ T _obs,cycle ) was 80 K, a notably large value. Such high ∆ T _obs,increase and ∆ T _obs,cycle values have not yet been reported for any caloric effect. Additionally, the barocaloric effect was highly repeatable without degradation. The reversible refrigerant capacity reached an unprecedented 26600 J kg ⁻¹ at 560 MPa, and the reversible adiabatic temperature change in one cycle (∆ T _ad,rev,cycle ) was estimated to be 134 K. This large temperature change in one cycle could inspire new applications, such as splitting liquid water into steam vapour and solid ice in one cycle of pressure application and release. These findings highlight the advantages of barocaloric solid state materials and open avenues for new cooling technologies.