Advanced nanoarchitectural superstructure hybridized with covalent organic nanosheets and 2H-MoS2 to boost the performance of sodium-ion batteries

Push–pull structured covalent organic nanosheets (CONs) are promising anode materials for sodium-ion batteries (SIBs) owing to their flexible π-conjugated frameworks and tunable porosity. In contrast, MoS 2 anodes have a high capacity but suffer from capacity degradation owing to their low intrinsic conductivity and volume expansion. To address these limitations, we developed a composite of 2H-MoS 2 nanosheets and multi-layered hollow CON spheres (CON/MoS 2 -HS). This composite was fabricated via the solvothermal synthesis of 2H-MoS 2 using CONs stacked on polystyrene beads as a template. CON/MoS 2 -HS exhibited improved electrical and ionic conductivities and reversible capacity, while its robust structural integration limited the changes in volume and mechanical stress during cycling, resulting in excellent long-term cycling stability. In contrast, reduced graphene oxide (rGO)/MoS 2 -HS was characterized by weaker interactions between rGO and 2H-MoS 2 , meaning that MoS 2 aggregation and volume expansion could not be prevented, thus compromising cycle stability and capacity. The CON/MoS 2 -HS electrode delivered a high reversible capacity of 671.8 mA h g −1 (~97% of the theoretical capacity) after 600 cycles at 100 mA g −1 and retained a capacity of 203.1 mA h g −1 after 5000 cycles at 5000 mA g −1 . The rate performance and long-term cycling stability of the CON/MoS 2 -HS electrode outperformed those of conventional MoS 2 -based anodes, demonstrating the strong synergistic relationship between the multilayered CON architecture and 2H-MoS 2 nanosheets. In this work, high-performance hybrid anodes were developed by integrating push-pull structured covalent organic nanosheets (CONs) with 2H-MoS 2 nanosheets. The CON/MoS 2 nano junction and hollow sphere structure provided a large contact area and shortened the ion/charge transport distance, significantly improving the Na + ion storage properties. • A hybrid anode (CON/MoS 2 -HS) was developed with covalent organic nanosheets and MoS 2 nanosheets. • The CONs framework provides rapid electron transport pathways, enhancing Na + storage kinetics. • The CON/MoS 2 -HS anode exhibits a high reversible capacity of 671.8 mA h g −1 . • The CON/MoS 2 -HS anode exhibits ~97% of the theoretical capacity and long-term cycle stability. • The hollow spherical nanoarchitecture facilitates rapid ion diffusion and buffers volume changes.