The Investigation of Electrochemical Properties Using High-Entropy Spinel-Oxide as an Anode for Lithium-Ion Batteries

The global demand for lithium-ion batteries (LIBs) is increasing, primarily because they can be used for various applications. To improve the energy density of LIBs, transition metal oxides are potential candidates for anodes owing to their high capacity and earth abundance. However, the issues such as low ionic conductivity, low Coulombic efficiency, and structural degradation during charge/discharge cycles limit the development of transition metal oxides in LIBs applications.<br/><br/>High-entropy oxides exhibit new chemistries and outstanding cycling stability for developing electrode materials. Nevertheless, they often contain expensive raw materials, and their effects on the application of LIBs are still unclear. In this work, a novel spinel-structure AMFCZ-based high-entropy oxide with five cost-effective and non-toxic oxides consisting of aluminum, manganese, iron, copper, and zinc ions is synthesized using a solid-state method with an ideal capacity of ~1000 mAh/g. Its cycling performance, electrochemical properties, and reaction mechanisms are investigated, showing good rate capability.<br/><br/>The slurries containing the AMFCZ-based active materials, carbon black (Super P), carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) are coated on a copper foil by using a doctor-blade process to form an electrode. After that, the electrode is dried in a vacuum oven, followed by assembling half-batteries in a glove box. The crystal structure of AMFCZ-based anode is characterized by X-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX) are used to analyze the morphology and composition distribution of AMFCZ-based anodes. Galvanostatic charge/discharge (GCD), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS) are used to analyze the cycling performance and electrochemical properties. This work reveals a novel high-entropy oxide as an anode and demonstrates its electrochemical properties as an anode for LIBs.