Proton-conducting materials serving as key components in various electrochemical and energy conversion devices have attracted a great deal of attention. The creation of superior proton-conducting materials in a wide temperature range under both humidified and anhydrous conditions is of great significance for practical applications. In this paper, we develop a coprecipitation synthesis approach for a new proton-conducting nanocomposite, [Bi₂O₂]H_x-PA_0.28, which consists of a layered framework with [Bi₂O₂]²⁺ and phytic acid (C₆H₁₈O₂₄P₆, abbreviated as PA) existing as interlayer-embedded charge-balancing anions. Infrared spectroscopy (FTIR), solid-state NMR, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) suggest that oxygen atoms on the surface of the [Bi₂O₂]²⁺ layer bridge the uncoordinated oxygen atoms on the phosphate group to form a strong hydrogen bonding network. This leads to a water-assisted proton conductivity of 1.76 × 10^–2 S cm^–1 at 90 °C under 98% RH and even a stable anhydrous proton conductivity of 5.24 × 10^–3 S cm^–1 at 150 °C. Isotope effect tests have verified the selective transmission of hydrogen ions by the composite electrolyte materials. [Bi₂O₂]H_x-PA_0.28 as electrolyte was further assembled into an ion-selective electrode for the recognition of hydrogen ions. Furthermore, open circuit potential time (OCPT) testing further confirms that solid-state electrolytes composed of [Bi₂O₂]H_x-PA_0.28 exhibit a good electrochemical stability. This work broadens the possibilities for the development of solid-state proton conductors in a wide temperature range, even under anhydrous conditions.

中文翻译：

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植酸改性的高稳定性铋基层状氧化物，可实现无水和水辅助质子电导率


质子导电材料作为各种电化学和能量转换器件的关键部件，引起了人们的广泛关注。在加湿和无水条件下，在较宽的温度范围内创造卓越的质子传导材料对实际应用具有重要意义。在本文中，我们开发了一种新的质子导电纳米复合材料 [Bi₂O₂]H_{x-PA 0.28} 的共沉淀合成方法，该方法由一个层状框架组成，其中 [Bi₂O₂]²⁺ 和植酸 （C₆H₁₈O₂₄P₆，缩写为 PA） 作为层间嵌入的电荷平衡阴离子存在。红外光谱 （FTIR）、固体核磁共振、拉曼光谱和 X 射线光电子能谱 （XPS） 表明，[Bi₂O₂]²⁺ 层表面的氧原子与磷酸基团上不配位的氧原子桥接，形成强氢键网络。这导致在 90 °C、98% RH 下水辅助质子电导率为 1.76 × ^10-2 S cm^–1，甚至在 150 °C 时稳定的无水质子电导率为 5.24 × 10^–3 S cm^–1。 同位素效应测试验证了复合电解质材料对氢离子的选择性传输。[Bi₂O₂]H_{x-PA 0.28} 作为电解质进一步组装成离子选择性电极，用于识别氢离子。此外，开路电位时间 （OCPT） 测试进一步证实，固态电解质由 [Bi₂O₂]H_{x-PA 0.28} 表现出良好的电化学稳定性。这项工作拓宽了在较宽温度范围内开发固态质子导体的可能性，即使在无水条件下也是如此。