Colossal Barocaloric Effect by Large Latent Heat Produced by First‐Order Intersite‐Charge‐Transfer Transition

Abstract

Materials which show novel thermal properties can be used to make highly efficient and environmentally friendly energy systems for thermal energy storage and refrigeration through caloric effects. An A-site-ordered quadruple perovskite-structure oxide, NdCu 3 Fe 4 O 12 , is found to release significant latent heat, 25.5 kJ kg −1 (157 J cc −1 ), at the intersite-charge-transfer transition temperature near room temperature. The transition is first-order and accompanied by an unusual magnetic ordering and a large negative-thermalexpansion-like volume change, and thus, it causes a large entropy change (84.2 J K −1 kg −1 ). The observed entropy change is comparable to the largest changes reported in inorganic solid materials, and more importantly, it is utilized through a colossal barocaloric effect. The adiabatic temperature change by applying 5.1 kbar pressure is estimated to reach 13.7 K, which means efficient refrigeration can be realized through this effect.

Colossal and reversible barocaloric effect in liquid-solid-transition materials n-alkanes

“…Calorimetric measurements under hydrostatic pressures were carried out using a home-built High-Pressure Differential Analysis (HPDTA) system. The similar equipment and related methods have been used in many previous reports 11 , 20 , 46 , 47 . One end of K-type thermocouple along with C n H 2 n +2 (MACKLIN, 99%) was sealed in a plastic capsule, and the other end along with the reference compound (i.e., C n H 2 n +2 with different n ) was sealed in another capsule.…”

“…The entropy change at the first order phase transition under ambient pressure was evaluated by the differential scanning calorimeter (DSC). Based on the DSC and DTA results, the entropy change of first-order phase transition under different pressures can be calculated 11 , 20 , 46 , 47 .…”

Colossal Barocaloric Effect in Carboranes as a Performance Tradeoff

“…The last few years have witnessed remarkable improvements in the performances of barocaloric materials after the discovery of colossal BCEs in plastic crystals. [21][22][23][24][25][26][27][28][29] As a hallmark, the entropy changes have rocketed to several hundreds of J kg −1 K −1 from about dozens of J kg −1 K −1 for leading caloric materials. Meanwhile, the driving pressures have been reduced down to below 100 MPa, compared to about 500 MPa for the previous barocaloric intermetallics.…”

Pressure dependence of atomic dynamics in barocaloric ammonium sulfate: I. Rotations

“…Because the high-entropy state can have many different physical origins, including orientational, vibrational, electronic, and configurational disorder, barocalorics are found among many different classes of materials. 3 Examples include shapememory alloys; 4 molecular and molecular-ionic crystals; [5][6][7][8][9] spin-crossover complexes; 10,11 and both inorganic 12 and molecular perovskites. 13,14 Such variety offers substantial hope that many more barocaloric materials are yet to be discovered.…”