A ZnO–graphene hybrid with remarkably enhanced lithium storage capability†
In this work, a ZnO–graphene (ZnO–GN) hybrid is successfully synthesized from graphene oxide (GO) and zinc hydroxide [Zn(OH)2] by a facile freeze drying treatment and subsequent heat treatment method. The uniform ZnO nanoparticles (NPs) with a diameter less than 10 nm were uniformly anchored on a nitrogen-doped conductive GN matrix to form a ZnO–GN hybrid. Moreover, various ZnO–GN hybrids with different ZnO loading amounts are fabricated by changing the dosage of Zn(OH)2. When used as an anode material for lithium ion batteries (LIBs), the hybrid showed unprecedentedly enhanced cycling stability and rate performance. More remarkably, the optimized ZnO–GN hybrid achieved an ultrahigh reversible capacity of 900 mA h g−1, close to the theoretical capacity (978 mA h g−1) of ZnO after 100 cycles at a current density of 100 mA g−1, which so far has been proved to be the best result among all ZnO–GN-based electrode materials. As a result, we attributed the excellent performance to the incorporation of the conductive nitrogen-doped GN matrix and the synergetic effect between GN sheets and ZnO NPs.