A rod-on-tube CoMoO4@hydrogel composite as lithium-ion battery anode with high capacity and stable rate-performance

Abstract Hierarchical materials have been considered promising for secondary battery electrodes owing to their capability of accommodating volumetric change of active materials and providing short pathways for rapid transportation of ions and electrons. Herein, we present a rod-on-tube composite consisting of cobalt molybdate (CoMoO4) nanotubes coating with polyaniline (PANI) hydrogel nanorods, which exhibits a high electrochemical performance as Li-ion battery anode. The hierarchical CoMoO4@PANI is prepared through in-situ polymerizing PANI nanorods on the CoMoO4 nanotubes. The rod-on-tube structure could alleviate the volumetric change of CoMoO4 during lithiation-delithiation, and improve conductivity for electron transfer. When cycling at 0.5 A g-1, the presented CoMoO4@PANI anodes exhibit a large capacity of 805 mAh g-1 after 150 cycles along with a Coulombic efficiency of 99%, which are both exceeding those of the pristine CoMoO4. A well-recoverable rate-performance is achieved. Furthermore, the density of state (DOS) and band gap of the CoMoO4@PANI and pristine CoMoO4 are also investigated by using density functional theory (DFT) calculations.