Synthesis and Optimization of Nanoparticle Ge Confined in a Carbon Matrix for Lithium Battery Anode Material

Ge nanoparticles with different particle sizes confined in a carbon matrix were prepared by annealing Ge nanoparticles terminated with butyl groups at 400, 600, and . X-ray diffraction and transmission electron microscopy results showed that the Ge nanoparticles' size increased from as the annealing temperature of the as-prepared samples increased from . Raman spectra confirmed that the parts of the Ge nanoparticles were not covered by the carbon starting at after annealing for . Moreover, the graphitization degree of the carbon increases with increasing temperature, and the sample, annealed at for , showed the graphitization degree. Electrochemical cycling results revealed that the Ge nanoparticles, confined in a carbon matrix obtained after annealing the as-prepared sample at for , showed the best charge capacity of with 12% capacity loss after . On the other hand, Ge nanoparticles that had not been covered with the carbon matrix showed a rapid capacity decrease, along with pulverization of Ge nanoparticles to a size of about after cycling.