Porous La-doped Fe₂O₃ (Fe₂O₃-La) nanorods have been synthesized through a facile hydrothermal method and subsequent heating process. The Fe₂O₃-La not only showed larger surface area, higher specific capacities and more stable cycle performances for lithium/sodium ion batteries, but also displayed much more excellent cycle and rate performances than the undoped Fe₂O₃ as an advanced sulfur host for lithium-sulfur batteries.

Abstract

Transition metal oxides are investigated as electrochemically active anodes for several years due to the merits of high specific capacity, low cost, abundant resources and controllable synthesis. But the poor cycle performances have hindered their further wide application. Herein, porous La-doped FeOOH nanorods have been synthesized through a facile hydrothermal method, which could be transformed into porous La-doped Fe₂O₃ (Fe₂O₃-La) via a simple heating process. Compared with the undoped Fe₂O₃, the Fe₂O₃-La showed larger surface area, higher specific capacities and more stable cycle performances for lithium/sodium ion batteries. In addition, as an advanced sulfur host for lithium-sulfur batteries, the Fe₂O₃-La also displayed much more excellent cycle and rate performances than the undoped Fe₂O₃. The superior electrochemical performances of the Fe₂O₃-La may could be attributed to the doping of La, which could induce more porous morphology and offer more reactive sites. The positive effects of La-doping for electrochemical performances of porous Fe₂O₃ nanorods provide novel insights for further applications of rare earth metal doping.