Lithium (Li) chloride and iron oxychloride (FeOCl), typically nonconductive, were combined to form a [Li_1+δCl]^δ+/[FeOCl]^δ− heterointerface composite material (LFH), achieving ionic conductivities of >1 mS cm⁻¹. Analysis techniques (scanning transmission electron microscopy [STEM] and electron energy-loss spectroscopy [EELS]) indicated that the microstructure of LFH consisted of an amorphous LiCl-based shell surrounding a crystalline FeOCl-based core. Electrochemical measurements alongside solid-state ^6,7Li nuclear magnetic resonance (NMR) and molecular dynamic simulations revealed Li⁺ as the sole conductive species, with a diffusion barrier of ∼0.25 eV. X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) results further supported interstitial Li⁺ diffusion at the heterointerface and within the LiCl phase, made possible by the heterointerface. Despite susceptibility to electronic conductivity, iron’s defects and multivalency (Fe³⁺, Fe²⁺) enable the Fe–O–Cl framework to accept Cl⁻, facilitating Li⁺ ionic conduction. A prototype solid-state cell (showing 97% Coulombic efficiency) demonstrated the viability of this heterointerface design for applications in energy storage.

中文翻译：

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通过设计和合成陶瓷异质界面实现快速离子传导


氯化锂 （Li） 和氯铁 （FeOCl），通常是不导电的，结合形成 [Li_1+δCl]^δ+/[FeOCl]^δ− 异质界面复合材料 （LFH），实现 >1 mS cm⁻¹ 的离子电导率。分析技术（扫描透射电子显微镜 [STEM] 和电子能量损失光谱 [EELS]）表明，LFH 的微观结构由围绕结晶 FeOCl 基核心的非晶态 LiCl 基壳组成。电化学测量以及固态 ^6,7Li 核磁共振 （NMR） 和分子动力学模拟显示 Li⁺ 是唯一的导电物质，扩散势垒为 ∼0.25 eV。X 射线光电子能谱 （XPS） 和 X 射线吸收精细结构 （XAFS） 结果进一步支持了异质界面和 LiCl 相内的间隙 Li⁺ 扩散，这由异质界面实现。尽管对电子导电性敏感，但铁的缺陷和多价性（Fe³⁺、Fe²⁺）使 Fe-O-Cl 框架能够接受 Cl⁻，从而促进 Li⁺ 离子传导。原型固态电池（显示 97% 的库仑效率）证明了这种异质界面设计在储能应用中的可行性。