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.