Zn-substituted CoCO3 embedded in carbon nanotubes network as high performance anode for lithium-ion batteries

Multicomponent composites with an atomic-scale distribution of different component and an integrated lattice structure may manifest an enhanced synergistic effect compared to the mechanical mixture. In this paper, multicomponent Zn0.12Co0.88CO3 composite with high tap density (2.11 g cm−3) synthesized via one-step solvothermal method, which exhibits hexagonal structure similar to that of the monocomponent cobalt carbonate (CoCO3). The Zn-substitution could significantly improve the charge and discharge capacity of CoCO3 from 1001.6 mAh g−1 to 1253.7 mAh g−1 at 0.2 C. When the Zn-substituted CoCO3 is embedded in carbon nanotubes (CNT) network, the rate performance of Zn0.12Co0.88CO3 can be improved greatly. The resulting Zn0.12Co0.88CO3/CNT exhibits outstanding rate performance, delivering a reversible capacity of 1098.4, 840.8, and 610.7 mAh g−1 at 0.5, 1 and 2 C, respectively. The excellent performance of Zn0.12Co0.88CO3/CNT is ascribed to the unique micro-sphere structure with carbon nanotubes. The elastic CNT networks are introduced to wrap the Zn0.12Co0.88CO3, which can not only provide a highly conductive network for electron transfer, but also serve as a buffer to alleviate the aggregation and volume changes of Zn0.12Co0.88CO3 nanoparticles. The Zn0.12Co0.88CO3/CNT composite may serve as a novel high-capacity LIBs anode material for practical application, and a facile strategic approach is introduced for the full-molar-ratio synthesis of multicomponent composites.