Electrocaloric effect (ECE) in ferroelectric (FE)/antiferroelectric (AFE) materials offers a promising high-efficient and zero-emission solid-state cooling technology, whose materials design is usually focused on the morphotropic phase boundary (MPB) between two FE phases. This work constructs an MPB between an orthorhombic AFE and a rhombohedral FE phase in Pb_0.97–xBa_xLa_0.02Zr_0.95Ti_0.05O₃ (PBLZT100x, x = 0–0.08) ceramics and achieves a superior ECE performance. An unprecedented high electrocaloric strength of 1.52 K·mm/kV and an ultrahigh refrigeration efficiency (coefficient of performance = 16) are obtained in PBLZT4, in the MPB near AFE end. Moreover, a large negative ECE, with the highest strength up to −0.41 K·mm/kV, is also realized due to the electric field-induced AFE–FE transition. The coexistence of giant positive and negative ECEs at adjacent temperatures can further improve the cooling capacity (∼17%) of solid-state refrigeration in a well-designed cooling cycle. This work provides a brand new materials design strategy to achieve giant positive and negative ECEs simultaneously and a novel cooling cycle to efficiently utilize the two effects.

中文翻译：

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通过变质相边界设计，反铁电陶瓷具有巨大的电热效应和超高制冷效率。

铁电（FE）/反铁电（AFE）材料中的电热效应（ECE）提供了一种有前途的高效零排放固态冷却技术，其材料设计通常集中于两个FE相之间的同相相界（MPB） 。这项工作在Pb _{0.97– x} Ba _x La _0.02 Zr _0.95 Ti _0.05 O ₃（PBLZT100 x，x= 0–0.08）陶瓷，并具有卓越的ECE性能。在靠近AFE端的MPB中的PBLZT4中，获得了前所未有的1.52 K·mm / kV的高电热强度和极高的制冷效率（性能系数= 16）。此外，由于电场引起的AFE-FE跃迁，还实现了大负ECE，其最大强度高达-0.41 K·mm / kV。在设计合理的冷却循环中，在相邻温度下同时存在巨大的正和负ECE可以进一步提高固态制冷的制冷能力（约17％）。这项工作提供了一种全新的材料设计策略，可同时实现巨大的正和负ECE，并提供了新颖的冷却周期来有效利用这两种效应。