Synthesis and electrochemical investigation of core-shell ultrathin NiO nanosheets grown on hollow carbon microspheres composite for high performance lithium and sodium ion batteries

In this article, a novel hierarchical core shell composite, namely, ultrathin NiO nanosheets grown on the surface of the hollow carbon (HC) microspheres, was designed and fabricated by a simple precipitation method followed by an annealing route. When evaluated as an anode material for lithium-ion batteries, the as-prepared core-shell HC@NiO composite delivers a specific capacity of 992 mAh g(-1) after 100 cycles at a current density of 0.5 A g(-1). As for sodium storage properties, its reversible capacity could be still preserved at 309 mAh g(-1) after 50 cycles at 0.1 A g(-1). The improved electrochemical performance of the HC@NiO composite for both lithium and sodium storage can be attributed to the good electrical conductivity of HC support and high loading content of ultrathin NiO nanosheets, which can not only improve the ion and electron transportation in the NiO phase, but also retarding the volume changes during the Li+/Na+ insertion/extraction process. (C) 2016 Published by Elsevier B.V.