Structure and thermal property relationships in the thermomaterial di--butylammonium tetrafluoroborate for multipurpose cooling and cold-storage

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 11; no. 41; pp. 22232 - 22247
• Main Authors: García-Ben, Javier, Bermúdez-García, Juan Manuel, Dixey, Richard J. C, Delgado-Ferreiro, Ignacio, Llamas-Saiz, Antonio Luis, López-Beceiro, Jorge, Artiaga, Ramón, García-Fernández, Alberto, Cappel, Ute B, Alonso, Bruno, Castro-García, Socorro, Phillips, Anthony E, Sánchez-Andújar, Manuel, Señarís-Rodríguez, María Antonia
• Format: Journal Article
• Published: 24.10.2023
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta04063a

Nowadays around 46% of food production around the world requires refrigeration, which is generally provided either by active vapour-compression (based on refrigerants with liquid-gas transitions) or passive cold-storage (based on solid-to-liquid phase change materials, SL-PCMs). However, in order to avoid fluid losses during the transitions, new thermomaterials with solid-solid transitions are desired for both applications. In this work, we find that [DBA][BF 4 ] (DBA = di- n -butylammonium) is a promising thermomaterial with solid-solid phase transitions. This compound presents thermal properties of great interest not only for active barocaloric refrigeration, but also for passive cold-storage, which make this a unique multipurpose thermomaterial. The observed cold-storage capacity is very close to that of commercial SL-PCMs ( E ∼ 135 kJ kg −1 ), while the pressure-induced thermal changes (Δ S ∼ [200-270] J K −1 kg −1 ) are superior to those of most barocaloric materials, operating under lower pressures ( p ∼ [500-1000] bar). Moreover, the operating temperature range of this material is very adequate for food preservation (250-310 K), which is a great advantage over most barocaloric materials. Beyond the thermal properties, we perform deep structural characterization, which reveals a progressive structural disorder of the [DBA] + cations and [BF 4 ] − anions as the origin of such thermal properties, which will help the future rational design of enhanced thermomaterials. The innovative [DBA][BF4] thermomaterial exhibits advanced thermal properties for multipurpose active barocaloric refrigeration and passive cold-storage of interest for commercial food preservation.