A growing number of cooling devices1–4 exploit large electrocaloric effects associated with a supercritically driven first-order ferroelectric phase transition in multilayer capacitors of PbSc0.5Ta0.5O3 (PST)5. However, these multilayer capacitors only operate above the room-temperature Curie temperature and require an energetically expensive 42-day anneal for high B-site order to maximize latent heat. Here we show that exaggerating valence mismatch through dilution with PbMg0.5W0.5O3 (PMW) maintains high B-site order and latent heat with no anneal, while disrupting dipolar order to reduce the Curie temperature as low as 230 K. Our multilayer capacitors of PST–PMW show supercritical electrocaloric effects of about 3 K across and well below room temperature owing to 17.1 V μm−1 fields we apply >107 times without breakdown. Using our multilayer capacitors in an ideal fluid regenerator and assuming work recovery yields cycle efficiencies of 70–90%. Taken together, our findings imply that multilayer capacitors of PST–PMW should now replace multilayer capacitors of PST in electrocaloric prototypes to permit electrocaloric refrigeration.
