Electrospun high-entropy metal oxide (NiMnCrCoFe)3O4 fiber anode for high-performance lithium-ion batteries

An emerging family of single-phase inorganic compounds, high-entropy oxides (HEOs) contain five or more metallic elements. Owing to their excellent electrochemical properties and structural robustness, they hold great promise for next-generation lithium-ion batteries (LIBs). In the present study, a porous spinel-structured high-entropy oxide with the composition (NiMnCrCoFe) 3 O 4 is fabricated via electrospinning as an anode. The structure and electrochemical performance of HEO nanofibers are evaluated across calcination temperatures of 700, 800, 900, 1000, and 1100 °C. At 900 °C, optimal rate capability (406.51 mAh g -1 at 2 A g -1 ) is achieved, along with a high reversible capacity of 604.42 mAh g -1 following 300 cycles at 0.1 A g -1 . The optimal performance at 900 °C is ascribed to a favorable balance between HEO crystallite growth and the structural inheritance derived from the oxidative decomposition of the polymer template. Excessively high temperature accelerates grain coarsening and induces excessive sintering, which causes severe particle aggregation and collapse of the fibrous architecture, thus reducing the availability of active sites. Benefiting from its scalability in nanomaterial manufacturing, electrospinning offers a practical means to address the large demand for anode materials in future lithium-ion batteries.