Co/La-Doped NiO Hollow Nanocubes Wrapped with Reduced Graphene Oxide for Lithium Storage

Abstract

Conversion-type NiO material is attractive due to its high theoretical capacity, and yet it displays inadequate reaction sites, a huge volume expansion, and a sluggish ions/electrons' transport rate in the lithium-ion battery (LIB) tests. In this work, metal organic framework (MOF) template and reduced graphene oxide (rGO) are employed to prepare hollow Co–La-doped NiO nanocubes/rGO nanocomposite. The design of a hollow nanocubes frame together with rich rough nanosheets could both provide abundant active sites and alleviate volume change during the lithiation/delithiation reaction. The conductive rGO network can not only significantly improve the electron transport of metallic oxide, but can also serve as a separator to inhibit the agglomeration of nanostructures. The doping of Co and La elements regulates the component of NiO structure and optimizes the ions/electrons' transport rate. Applied to the LIB anode material, this nanocomposite harvests a nice specific capacity (first discharge capacity of 1279.6 mAh g–1 and average capacity of 726.9 mAh g–1 at 0.1 A g–1). Besides, after 500 repeated cyclic tests at a high current density of 1 A g–1, the specific capacity still retains 434.1 mAh g–1. Structural characterization and electrochemical analysis well disclose that the significantly enhanced electrochemical performance is benefited from a distinct hollow structure, regulation of La content, and incorporation with rGO, which further highlights the suitable structural design and composition regulation.