RESUMEN
Heterostructured Fe2O3/Fe7S8 hollow fibers were rationally designed and synthesized via the electrospinning technique, followed by a calcination process and sulfuration treatment. Benefitting from the synergistic effect of the hollow structure and the built-in electric field induced by the heterostructure, the as-prepared Fe2O3/Fe7S8 composite anode exhibits high specific capacity (947 mA h g-1 after 100 cycles at 0.2 A g-1), excellent rate capability, and long-term cycling stability (730 mA h g-1 after 1000 cycles at 1 A g-1).
RESUMEN
Transition-metal oxides (TMOs) are promising anode materials for high-performance lithium-ion batteries (LIBs) because of their abundant reserves and high theoretical capacity. However, the poor conductivity, unstable solid electrolyte interface (SEI) film, and poor cycling stability still limit their practical applications. As a novel kind of anode material, a high-entropy oxide (HEO) is a single-phase crystal structure composed of multiple metal elements, demonstrating a huge potential for energy storage applications due to the synergistic effect of various metal species. Herein, we have designed the porous spinel-phase HEO (Cr0.2Fe0.2Co0.2Ni0.2Zn0.2)3O4 synthesized at low temperature by a sol-gel method. On the one hand, the unique porous nanostructure not only promotes transport of the electrolyte but also alleviates the volume change of active materials upon cycling. On the other hand, the stabilization effect of entropy can suppress the formation of cation short-range order within the crystalline structure of HEO by a lattice distortion effect, thus guaranteeing a fast lithium-ion transport and achieving an excellent electrochemical performance. As a result, the as-prepared HEO-450 electrode delivers 1022 mAh/g after 1000 cycles at 1 A/g and 220 mAh/g at an ultrahigh current density of 30 A/g, respectively.