Enhancing the Electrochemical Properties of Silicon Nanoparticles by Graphene-Based Aerogels

Herein, silicon nanoparticles (nSi) are produced by magnesiothermic reduction methods. nSi are then obtained in the form of a 3D graphene aerogel (GA), prepared by a simple one-step freeze-drying process using L-ascorbic acid. By a simple freeze-drying process, nSi is neatly decorated between sheets of graphene. GA forms a conductive structure for nSi whose mechanical mesh acts as a buffer layer. This conductive structure greatly improves the structural integrity and conductivity of the anode material. Nanoparticles silicon/graphene aerogel (nSi/GA) nanocomposite is investigated by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. nSi/GA nanocomposite demonstrates a superior capacity of 550 mAh g(-1) after 500th cycle. As a result, the nSi/GA anodes show improvement in cycling stability compared with pure nSi. Tests are conducted at different rate capability to measure the velocity characteristic and the resulting anode exhibits average specific discharge capacities of 1217, 976, 919, 825, 674, and 572 mAh g(-1) at charge/discharge rates of C/20, C/10. C/5, 1C, 3C, and 5C, respectively. Benefiting from easy synthesis and excellent cyclic stability, nSi/GA are expected to play an important role in the lithium-ion battery.

Automated summary

Silicon nanoparticles (nSi) are obtained by magnesiothermic reduction methods and then incorporated into a 3D graphene aerogel (GA) via a simple freeze-drying process. The GA serves as a conductive structure and a buffer layer for the nSi, improving the structural integrity and conductivity of the anode material. The nSi/GA nanocomposite exhibits excellent cyclic stability and a capacity of 550 mAh g(-1) after 500 cycles.