  A material with reversible temperature change capability under an external
electric field, known as the electrocaloric effect (ECE), has long been
considered as a promising solid-state cooling solution. However, electrocaloric
(EC) performance of EC materials generally is not sufficiently high for real
cooling applications. As a result, exploring EC materials with high performance
is of great interest and importance. Here, we report on the ECE of
ferroelectric materials with van der Waals layered structure (CuInP2S6 or CIPS
in this work in particular). Over 60% polarization charge change is observed
within a temperature change of only 10 K at Curie temperature. Large adiabatic
temperature change (|{\Delta}T|) of 3.3 K, isothermal entropy change
(|{\Delta}S|) of 5.8 J kg-1 K-1 at |{\Delta}E|=142.0 kV cm-1 at 315 K (above
and near room temperature) are achieved, with a large EC strength
(|{\Delta}T|/|{\Delta}E|) of 29.5 mK cm kV-1. The ECE of CIPS is also
investigated theoretically by numerical simulation and a further EC performance
projection is provided.
