Record high-T<sub>c</sub> and large practical utilization level of electric polarization in metal-free molecular antiferroelectric solid solutions.

Xu, Haojie; Guo, Wuqian; Ma, Yu; Liu, Yi; Hu, Xinxin; Hua, Lina; Han, Shiguo; Liu, Xitao et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

Metal-free antiferroelectric materials are holding a promise for energy storage application, owing to their unique merits of wearability, environmental friendliness, and structure tunability. Despite receiving great interests, metal-free antiferroelectrics are quite limited and it is a challenge to acquire new soft antiferroelectric candidates. Here, we have successfully exploited binary CMBrxI1-x and CMBrxCl1-x solid solution as single crystals (0 ≤ x ≤ 1, where CM is cyclohexylmethylammonium). A molecule-level modification can effectively enhance Curie temperature. Emphatically, the binary CM-chloride salt shows the highest antiferroelectric-to-paraelectric Curie temperature of ~453 K among the known molecular antiferroelectrics. Its characteristic double electrical hysteresis loops provide a large electric polarization up to ~11.4 μC/cm2, which endows notable energy storage behaviors. To our best knowledge, this work provides an effective solid-solution methodology to the targeted design of new metal-free antiferroelectric candidates toward biocompatible energy storage devices.