Facile shape design and fabrication of ZnFe2O4 as an anode material for Li-ion batteries

Abstract

Functional materials with exposed highly reactive planes have attracted considerable attention with respect to their enhanced electrochemical energy storage. However, highly active facets of ZnFe₂O₄ nanocrystals usually have high surface energy, and thus are hard to prepare in the equilibrium state or via traditional methods. In this regard, we propose a novel strategy to fabricate cubic, truncated octahedral, and octahedral ZnFe₂O₄ by a convenient hydrothermal method and subsequent thermal treatment for the first time. The ZnFe₂O₄ octahedra exhibit a reversible capacity of 450 mA h g⁻¹ at a current density of 60 mA g⁻¹ after 50 cycles, while the reversible capacity of ZnFe₂O₄ cubes is 367 mA h g⁻¹. The electrochemical performance of the three types of ZnFe₂O₄ can be ranked as “octahedron > truncated octahedron > cube”. The exposed planes, which are filled with a high density of atoms, lead to the better electrochemical performance.