Recent advances and innovations in elastocaloric materials for solid-state refrigeration

Elastocaloric refrigeration technology is a highly efficient and environmentally friendly solid-state alternative to conventional vapor-compression refrigeration systems, leveraging the elastocaloric effects generated during the stress-induced martensitic transformations in shape memory alloys (SMAs). The cooling performance of this emerging technology primarily depends on the comprehensive properties of SMAs, which serve as the refrigerants. To date, various SMAs, such as Ni–Mn-based, Ni–Ti-based, Co-based, Ni–Fe–Ga-based, and Cu-based alloys, have demonstrated significant elastocaloric effects. However, the development of elastocaloric refrigeration applications is often severely hindered by other crucial properties of these SMAs, such as transformation temperature, transformation stress, stress hysteresis, coefficient of performance (COP), fatigue resistance, and cost. In this article, we provide a concise overview of recent research progress in elastocaloric performance across various SMAs, with a focus on the optimization strategies and the underlying microstructural mechanisms. Meanwhile, this review aims to provide actionable guidance and a comprehensive roadmap for the development of high-performance SMAs, facilitating the transition from laboratory-scale breakthroughs to practical elastocaloric refrigeration applications in the near future.