Formation of hierarchical Fe7Se8 nanorod bundles with enhanced sodium storage properties

Ordered hierarchical architectures are attractive candidates for electrochemical energy storage applications. Herein, a facile self-template strategy is applied to prepare Fe7Se8 architectures with a monolithic structure via a self-synthesized single precursor and subsequent calcination at high temperature. With the support of oleylamine, the precursor is structurally targeted to engineer the Fe7Se8 microstructure, featuring nanorod bundles arranged along the longitudinal direction. Because of their ordered hierarchical structure, the Fe7Se8 nanorod bundles deliver a high reversible capacity of 300 mAh g(-1) at 0.5 A g(-1), along with exceptional rate capability up to 20 A g(-1) and long-term cycle life over 8000 cycles, which represents the highest stability of Fe7Se8 anodes for sodium-ion batteries reported to date. The feasibility of the present strategy to prepare metal selenide structures highlights its promising potential for the rational and effective engineering of electrode materials responsible for the electrochemical performance of energy storage systems. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.