Three-dimensional honeycomb-like porous carbon embedded with Ge nanoparticles anode composites for ultrastable lithium storage

Abstract

Designing a kind of electrode material with effective morphology and structural function is always a topical issue in the field of electrochemical energy storage. Herein, we report a simple and scalable NH4Cl/KOH etching method to construct the three-dimensional honeycomb-like porous carbon material derived from biomass sweet potato starch, then load Ge nanoparticles for the use as anode material. This three-dimensional honeycomb material contains uniform cavities with size of 3–6 µm, which can provide more space for the adsorption of Ge nanoparticles because of a higher specific surface area and an increased graphitization degree. This specific structure can maintain stability and mitigate the effect of volume expansion of Ge nanoparticles, while it can effectively improve the electronic conductivity and electrochemical activity of the Ge-BSPPC composite. Therein, the honeycomb porous Ge-BSPPC composite exhibits excellent discharge capacity and ultrastable lithium storage ability: the initial discharge capacity of 1257 mAh g−1, with the initial coulombic efficiency of 85.4%; the stable capacity after 100 cycles of 1025 mAh g−1, with the coulombic efficiency of 97.8%. This method provides a simple and cost-efficient approach for converting biomass into high-performance electrode materials.