Simple and low-cost ionic plastic crystal for multipurpose cold storage and barocaloric thermal management

Abstract

In the current energy transition scenario, refrigeration and cold preservation are critical to reach the Sustainable Development Goals of the United Nations (SDG-UN). Nowadays, the refrigeration market pressed by international regulations is seeking new alternatives to hazardous and greenhouse refrigerant gases to reduce both carbon emissions and energy consumption. From a humanitarian perspective it is urgent to decrease the annual food losses related to failures in the cold chain, which particularly strains countries and regions with unreliable access to electrical power grids. In this work, we present a simple, economic and easy-to-manufacture solid-state thermomaterial ([CH3NH3][BF4]) that presents very large thermal and caloric properties of interest for multipurpose cold storage (E ~ 89 J g-1) and barocaloric refrigeration (ΔS ~175 J K-1 kg-1, ΔT ~13 K), which could be implemented in both on-grid and off-grid cooling technologies. This material exhibits thermal performance comparable to both commercial cold storage materials and emerging barocaloric materials combined in the same compound. Furthermore, we analyse the structural origin of these thermal properties in order to provide insights for the design of future thermomaterials with enhanced properties.