F127/PDA dual-assisted fabricating high dispersed Ge nanoparticles/N-doped porous carbon composites with efficient lithium storage

Nanocrystallization and carbon composite are effective methods to solve the mechanical instability and low conductivity of Ge-based anode materials. In this work, a meaningful phenomenon is discovered that F127 can effectively disperse GeO2 polycrystalline particles, which facilitates the formation of Ge nanoparticles embedded in N-doped carbon (Ge/N-C) composites. Polydopamine (PDA) has cross-linking effect, effectively alleviating the reaggregation of GeO2 nanoparticles, and its derived N-doped carbon ensures the uniform dispersion and independent structure of Ge nanoparticles. When assessed as anode material for lithium-ion batteries (LIBs), Ge/N-C composites exhibit a high discharge capacity of 1323 mA h g-1in the second cycle at 0.2 A g-1 and 981 mA h g-1 after 100 cycles, with a capacity retention rate of 74%. Additionally, the composites show high-rate capability of 959 mA h g-1at 2 A g-1. The excellent lithium storage performance is attributed to that the synergistic effect between three-dimensional carbon network structure and Ge nanoparticles, which provides stable mechanical structure and abundant redox sites, suppressing volume expansion and accelerating the electrochemical reaction kinetics. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Nanocrystallization and carbon composite are effective methods to solve the mechanical instability and low conductivity of Ge-based anode materials. In this study, F127 was found to disperse GeO2 polycrystalline particles effectively, facilitating the formation of Ge nanoparticles embedded in N-doped carbon composites. The main objective was to evaluate the performance of the composite material as an anode material for lithium-ion batteries. The experimental results showed that Ge/N-C composites exhibited high discharge capacity, good capacity retention rate, and high-rate capability. The excellent lithium storage performance was attributed to the synergistic effect between the three-dimensional carbon network structure and Ge nanoparticles.