A review from elasto- to twistocaloric cooling

As a significant branch of solid-state cooling, elastocaloric and twistocaloric cooling achieve reversible temperature changes through the mechanical deformation of functional materials. Compared to vapor-compression refrigeration, they have emerged as promising alternatives because of high efficiency, environmental compatibility, and structural flexibility. Among various cooling strategies, twistocaloric cooling has recently attracted growing attention owing to its large temperature changes under low driving stress through torsional deformation. Here, we summarize recent progress in flexible twistocaloric and elastocaloric materials and devices, covering shape memory alloys, elastomeric polymers, and other emerging polymers. We elucidate the cooling mechanisms from molecular levels and compare the cooling properties among kinds of cooling materials. Then, large- and small-scale cooling devices driven by twisting, uniaxial stretching, and hybrid deformation are clarified, and critical discussions on heat-transfer efficiency, mechanical stability, and scalability are emphasized. Finally, key challenges and future opportunities are outlined from material optimization, device engineering and multi-mode integration, and theoretical modeling perspectives, highlighting pathways toward compact, durable, and energy-efficient solid-state cooling technologies.