Abnormal temperature-dependent electrical conduction in ZnAl-layered double hydroxide nanostructures

Abstract Layered double hydroxides (LDHs) have recently emerged as promising materials for various device applications due to their controllable properties depending on the type or ratio of cations and anions constituting the crystal structure. Despite active research on the electrical, electrochemical, and photochemical applications of LDH nanostructures, their electrical conduction mechanism and the correlation between their temperature-dependent electrical and structural properties have rarely been investigated. Herein, we report on the abnormal temperature-dependent electrical property of the ZnAl-LDHs and verify its origin based on in-situ structural and chemical investigations. The electrical conductivity of the ZnAl-LDHs increased continually with increasing temperature from 25 to 55℃, but then decreased drastically as the temperature was further raised to 115℃. During cooling back to room temperature, the conductivity decreased gradually with decreasing temperature. The temperature-dependent chemical and structural investigations verified that the water content and composition of anions in the ZnAl-LDHs were changed by the temperature variation, which resulted in the abnormal electrical properties of the ZnAl-LDHs.