Ionic conductors serve as solid electrolytes for fuel cells and batteries, whereas polar crystals such as ferroelectrics and pyroelectrics—which are typically insulating materials—are used in electronic devices. Here we show a material that combines superionic conductivity with a polar crystal structure at room temperature. This three-dimensional anionic network is based on –Fe–N≡C–Mo– units, with Cs cations hosted in every other pore. In the resulting Cs_1.1Fe_0.95[Mo(CN)₅(NO)]·4H₂O material, the negative and positive charges of the framework and Cs⁺ ions, respectively, are non-symmetrically shifted in the c-axis direction of the unit cell, and spontaneous electric polarization is generated, in turn leading to second harmonic generation (SHG). Additionally, this material is a superionic conductor (with an ionic conductivity value of 4 × 10⁻³ S cm⁻¹ at 318 K). Furthermore, the ionic conductivity significantly decreases under 532 nm light irradiation (from 1 × 10⁻³ S cm⁻¹ to 6 × 10⁻⁵ S cm⁻¹ at room temperature) and, when irradiation stops, returns to its original value within ~1 h.

离子导体用作燃料电池和电池的固体电解质，而极性晶体（例如铁电和热电）（通常是绝缘材料）则用于电子设备中。在这里，我们展示了一种在室温下结合了超离子传导性和极性晶体结构的材料。该三维阴离子网络基于–Fe–N≡C–Mo–单元，且Cs阳离子存在于其他孔中。在所得的Cs _1.1 Fe _0.95 [Mo（CN）₅（NO）]·4H ₂ O材料中，骨架和Cs ⁺离子的负电荷和正电荷分别在c中不对称地移动。单元电池的轴向方向，并产生自发极化，进而导致二次谐波（SHG）。另外，该材料是超离子导体（在318 K下离子电导率为4×10 ^-3  S cm ^-1）。此外，在532 nm的光照射下，离子电导率显着降低（从室温下的1×10 ^-3  S cm ^-1到6×10 ^-5  S cm ^-1），并且当停止照射时，离子电导率恢复到〜内的原始值。 1小时