A novel lollipop-shaped Co₃O₄@MnO₂ composite has been successfully developed and evaluated as a high-performance anode material for lithium-ion batteries (LIBs). The unique architecture consists of porous Co₃O₄ polyhedrons (1 µm in diameter) attached to MnO₂ nanotubes (100 nm in diameter), forming a hierarchical structure that synergistically combines the advantages of both transition metal oxides. The synthesis strategy involves growing zeolitic imidazolate framework-67 (ZIF-67), a cobalt-based metal–organic framework, on the open ends of pre-synthesized MnO₂ nanotubes via a self-assembly process. Subsequent calcination under air atmosphere transforms ZIF-67 into Co₃O₄ while preserving the original lollipop morphology. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) confirm the formation of well-defined nanostructures with excellent crystallinity.
Electrochemical evaluations demonstrate outstanding performance. The Co₃O₄@MnO₂ electrode delivers a reversible capacity of 1080 mAh g⁻¹ after 160 cycles at 300 mA g⁻¹ and maintains 696 mAh g⁻¹ even at a high current density of 1 A g⁻¹ after 210 cycles.GLUT3 Antibody Purity & Documentation This significantly outperforms pure Co₃O₄ polyhedrons (404 mAh g⁻¹ at 300 mA g⁻¹) and MnO₂ nanotubes (590 mAh g⁻¹ at 300 mA g⁻¹), highlighting the superior rate capability and cycling stability enabled by the composite design. Cyclic voltammetry reveals stable redox peaks corresponding to the reduction of Co₃O₄ to metallic Co and MnO₂ to Mn, along with oxidation processes during charge, indicating good reversibility.NRG3 Antibody In Vivo Electrochemical impedance spectroscopy (EIS) shows lower charge transfer resistance compared to individual components, attributed to enhanced electrical conductivity from Co₃O₄ and increased interfacial contact area due to the porous structure.PMID:35212165
The structural integrity of the lollipop architecture is preserved even after prolonged cycling, as confirmed by post-cycling TEM and selected area electron diffraction (SAED). While the Co₃O₄ head becomes partially amorphous, the MnO₂ nanotube backbone retains its crystalline order, suggesting effective buffering against volume expansion during lithiation/delithiation. The presence of void spaces between the components alleviates mechanical stress, preventing pulverization and degradation. Additionally, the 1D nanotubular MnO₂ provides efficient electron and ion transport pathways, further enhancing kinetics.
The exceptional electrochemical behavior stems from strong synergetic effects: MnO₂ enhances the reversibility of the reaction mechanism, while Co₃O₄ improves electronic conductivity. Together, they enable rapid Li⁺ insertion/extraction and maintain structural stability over extended cycling. The calculated theoretical capacity of the composite (959 mAh g⁻¹) is surpassed by the experimental result (1080 mAh g⁻¹), confirming significant synergistic contributions beyond simple additive effects.
In conclusion, this lollipop-structured Co₃O₄@MnO₂ composite represents a promising anode candidate for next-generation high-energy-density LIBs. Its rational design, combining tailored morphology and dual-metal oxide synergy, offers a powerful strategy for overcoming intrinsic limitations of transition metal oxide materials, paving the way for advanced energy storage systems.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com