In situ growth of ZnO nanodots on carbon hierarchical hollow spheres as high-performance electrodes for lithium-ion batteries

Abstract

Metal-organic frameworks (MOFs) is an ideal class of precursors or templates to build up transition metal based composites with unique architectures and high electrochemical performance for energy storage applications. In this work, a hybrid hollow nanoarchitecture made of ultrasmall zinc oxide nanodots (less than 5 nm in diameter) and carbon with 3D ordered hollow structure have been synthesized through a simple surfactant-assisted hydrothermal method followed by thermal annealing treatment. This 3D ordered hollow structure not only offers good electronic transportation routes and ionic conductive channels, but also effectively relieves the stress and mitigates the volume variation during lithiation/delithiation process as reflected by the high cycle stability and excellent rate capability as anode materials for lithium ion batteries. Benefitting from the rational design of 3D hollow structure and the synergistic effect between the ultrasmall ZnO nanodots and carbon framework, the ZnO/C hollow structures exhibit decent electrochemical performance of lithium storage with excellent cycling stability (a reversible capacity of 919 mA h/g over 100 cycles at 100 mA/g) and enhanced rate capability (567 mA h/g at high current density of 2 A/g). In addition, it also can deliver a capacity of 741 mA h/g at 500 mA/g after 120 cycles. These results uncover a facile route for the material design for energy application.