Synergistic Interactions of Different Electroactive Components for Superior Lithium Storage Performance

Synthesis of Co@CoO/C by micro-tube method and their electrochemical performances

Lithium-ion batteries (LIBs) are promising secondary batteries that are widely used in portable electronic devices, electric vehicles and smart grids. The design and synthesis of high-performance electrode materials play a crucial role in achieving lithium-ion batteries with high energy density, prolonged cycle life, and superior safety. CoO has attracted significant attention as a negative electrode material for lithium-ion batteries due to its high theoretical capacity and abundant resources. However, its limited conductivity and suboptimal cycling performance impede its potential applications. The study proposes a novel micro-tube reaction method for the synthesis of Co@CoO/C, utilizing Kapok fiber as a template with a special hollow structure. The microstructure and composition of the samples were characterized using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After conducting electrochemical performance tests, it was discovered that at a current density of 100 mA/g and within the range of 0.01-3.0 V for 50 charge and discharge cycles. Co@CoO/C composite negative electrode exhibits a reversible lithium insertion specific capacity of 499.8 mAh/g and keep a discharge capacity retention rate of 97.6 %. The greatly improved lithium storage and stability performance of Co@CoO/C composite anode is mainly attributed to the synergistic effect between Co@CoO nanoparticles and the kapok carbon microtubule structure.

Facile construction of ZnWO4/ZnO porous nanoplates on reduced graphene oxide for superior lithium storage

Zinc tungstate (ZnWO4) shows great promise as an anode material for lithium-ion batteries (LIBs) owing to its reversible multi-electron redox reactions and high theoretical capacity. Nevertheless, the low conductivity and big strain during cycling can lead to the inferior electrochemical properties of the ZnWO4 anode, hindering its practical application. Herein, we report a novel composite with ZnWO4/ZnO porous nanoplates in-situ constructed on reduced graphene oxide (rGO) by a metal-organic framework template strategy. The nanoplates with good porosity are composed of nanoparticles and nanorods, providing a short Li+-diffusion distance and plentiful Li+ storage active sites. The introduction of rGO can accelerate charge transfer and reinforce structural stability. As a result of these advantages, the ZnWO4/ZnO/rGO composite as LIBs anode delivers a high reversible capacity of 811 mAh g after 100 cycles at 200 mA g-1, excellent rate capability (437 mAh g at 5000 mA g-1), and good long cycling stability (485 mAh g after 500 cycles at 2000 mA g-1). Notably, the rate capability of the composite far precedes the previously reported ZnWO4-based anodes. This work provides an efficient approach for designing and fabricating advanced metal tungstate-based anodes for high-performance LIBs.