Barocaloric effect and materials: A review

As the global energy crisis and environmental issues intensify, the development of efficient and environmentally friendly novel refrigeration technology has become a significant focus in the field of scientific research and engineering. Conventional vapor compression refrigeration utilizes vapor refrigerants with high global warming potentials, which not only consume huge amounts of energy but also adversely affect the environment. In recent years, solid-state refrigeration technology has emerged as a research hotspot because of its controllable refrigerants, high energy efficiency, and environmental friendliness. Among the various refrigeration technologies that yield caloric effects through external-field-induced phase transitions, barocaloric refrigeration technology has been highly anticipated due to its low required driving pressure for refrigerant materials, large entropic change upon phase transition, and potentially high efficiency. On the other hand, many types of barocaloric materials are currently available, including intermetallic compounds, inorganic and organic materials, as well as organic–inorganic hybrid materials. Based on the barocaloric effect mechanism and the fundamental principles of various barocaloric materials, this paper summarizes the latest research in this field. It reviews the origins of the caloric effects of different types of barocaloric materials. The future development directions and application prospects of barocaloric solid-state refrigeration technology and materials are outlined.