Three-dimensional hierarchical graphene and CNT-coated spinel ZnMn2O4 as a high-stability anode for lithium-ion batteries

ZnMn 2 O 4 , with theoretical specific capacity of 1008 mAh g −1 , is a promising anode material for lithium-ion batteries. It attracts intensive research interests not only because of its high specific capacity, but also due to its low cost, abundant resources and environmental friendliness . However, its poor reaction kinetics, low intrinsic electrical conductivity and large volume changes upon cycling impede its commercial application. In this work, we demonstrate a method to effectively synthesize a three-dimensional, layered network architecture utilizing reduced graphene oxide (rGO) and cross-linked carbon nanotubes (CNTs) as substrates for ZnMn 2 O 4 nanoparticles . The ZnMn 2 O 4 nanoparticles are grown in-situ on the surface of both the rGO and the CNTs. The results show that the composite samples display a significantly enhanced electrochemical performance when compared with their pristine counterparts. In particular, the ZnMn 2 O 4 -rGO/CNT composite anode delivered an enhanced capacity of 606 mAh g −1 at 1.0 A g −1 after 1000 cycles with an 83% capacity retention. The synergistic effect between the rGO and the CNTs is believed to be the reason for the improved performance. In-situ X-ray diffraction (XRD) was used to successfully reveal the electrochemical conversion reaction mechanism of the new ZnMn 2 O 4 anode.