| 초록 |
Recently, electrochemical energy storage devices such as lithium rechargeable batteries and supercapacitors have attracted considerable attention because of the rapid growth of their applications in portable electronic devices, electric vehicles, and large-scale energy storage systems. To meet the ever-growing demand for energy density, various electrode materials have been actively examined. In this work, an efficient microstructure comprising different nanostructure interconnections was desinged. By adopting a bottom-up self-assembly process via a one-pot solvothermal method, cluster microspheres were synthesized, where Nb2O5 particles with diameters of a few tens of nanometers were connected by incorporating Ge/GeO2 nanonets. Ge-based materials were selected because their electrical conductivity is better than that of Si-based materials and because they still act as high-capacity lithium storage materials by using electrochemical alloying reactions. Moreover, Nb2O5 materials exhibit considerably small volume changes during Li insertion/extraction processes, and thus, they can be used as a buffer medium for the volume changes of Ge-based nanonets. The electrochemical tests demonstrated that the Nb2O5–Ge/GeO2 microsphere electrodes show a reversible specific capacity of more than 600 mAh g−1, a stable capacity retention of up to 1000 cycles, and an excellent rate performance. |
