Three-dimensional TiNb2O7 anchored on carbon nanofiber core-shell arrays as an anode for high-rate lithium ion storage

Abstract

The control of structure and morphology in an electrode design for the development of large-power lithium ion batteries is crucial to create efficient transport pathways for ions and electrons. Herein, we report a powerful combinational strategy to build omnibearing conductive networks composed of titanium niobium oxide nanorods and carbon nanofibers (TNO/CNFs) via an electrostatic spinning method and a hydrothermal method into free-standing arrays with a three-dimensional heterostructure core/shell structure. TNO/CNF electrode exhibits significantly superior electrochemical performance and high-rate capability (241 mA h g-1 at 10C, and 208 mA h g-1 at 20C). The capacity of the TNO/CNF electrode is 257 mA h g-1 after 2000 cycles at 20C, which is much higher than that of the TNO electrode. In particular, the TNO/CNF electrode delivers a reversible capacity of 153.6 mA h g-1 with a capacity retention of 95% after 5000 cycles at ultrahigh current density. Superior electrochemical performances of the TNO/CNF electrode are attributed to the unique composite structure.