Fe-Containing High-Entropy Oxides: An Advanced Material System for Lithium-Ion Battery Anodes

The rapid proliferation of mobile communication devices and the sustained expansion of the electric vehicle market have engendered an escalating urgency for research into next-generation, high-performance lithium-ion battery (LIB) technology. Crucial electrochemical characteristics of LIBs, such as energy density, charge/discharge rate capability, and cycling durability, are predominantly dictated by the performance metrics of their core constituent: the anode material. High-entropy oxides (HEOs), due to their unique multi-component composition and entropy-stabilized structure, offer tunable physicochemical properties and exceptional structural stability, making them promising candidates as next-generation anode materials for lithium-ion batteries (LIBs). Among them, Fe-containing high-entropy oxides have abundant iron element reserves, low in cost, and exhibit good electrochemical activity. Furthermore, when Fe is combined with other elements, it can enhance the energy storage capacity and service life of the battery. This review systematically outlines the recent progress in the application of Fe-containing High-Entropy Oxides (Fe-HEOs) as anode materials for lithium-ion batteries (LIBs). The content primarily focuses on the rational design principles, synthesis strategies (including solid-state, liquid-phase, and gas-phase methods), and the optimization mechanisms influencing their electrochemical performance. Furthermore, this paper discussed the significance of various advanced characterization techniques in elucidating the compositional structure of Fe-HEOs and their role in facilitating the enhancement of their electrochemical properties. Critically, this review also addressed the current challenges and future research directions, aiming to provide a theoretical basis and practical reference for the rational design of high-performance, cost-effective Fe-HEO anode materials.