One-pot synthesis of ZnAl double hydroxide powders and their calcined oxide composites for lithium-ion battery applications

In this work, we introduce a process for facile synthesis of ZnAl layered double hydroxide (LDH) powders and their calcined oxide composites for use in energy storage applications. First, Zn²⁺+ cations are isomorphously substituted by Al³⁺ cations, then ZnAl LDH structures are obtained using a hydrothermal method. Subsequently, ZnAl LDH powders are calcined under argon gas to create Li-ion battery anode materials. After thermal decomposition, ZnAl LDH structures are changed into nanoporous ZnO/ZnAl₂O₄ mixed metal oxides (MMO), which retain the plate-like structures of ZnAl LDH. To evaluate the electrochemical properties of ZnO/ZnAl₂O₄ MMO for Li-ion battery applications, a galvanostatic lithiation-delithiation test is applied to the coin-type half cells. Moreover, carbon-coating was introduced on MMO composites to improve their poor electrical conductivity. We found that the electrochemical performances of carbon-coated ZnO/ZnAl₂O₄ MMO composites were greatly improved by the enhanced electrical conductivity, compared to pristine MMO powders, as confirmed by the electrochemical impedance spectroscopy.