Synergistic effects from super-small sized TiO2 and SiOx nanoparticles within TiO2/SiOx/carbon nanohybrid lithium-ion battery anode

摘要

TiO2/SiOx/carbon nanohybrid consisting of super-small sized TiO2 and SiOx nanoparticles is in situ formed within the in situ formed carbon matrix using difunctional methacrylate monomers as solvent and carbon source. The relative composition of TiO2 and SiOx is systematically tuned by varying the feeding mass ratio of the precursors (TEOS/TTIP) and HF etching treatment after the carbonization process. The super-small sized TiO2 and SiOx nanoparticles are well intermixed with each other and homogeneously dispersed throughout the carbon matrix, where a good control over crystallinity, morphology, and microstructure of the nanohybrids is achieved. Synergistic effects are demonstrated from both TiO2 and SiOx regarding the increased reversible capacity from the SiOx phase and maintenance of good cyclic stability by the TiO2 component when being used in lithium-ion batteries. A good balance is achieved in terms of reversible capacity, capacity retention, and rate performance in the TiO2/SiO2/C nanohybrid prepared with the TEOS/TTIP mass ratio of 1.0. The reversible capacities are improved by around two times compared to the SiOx free sample with a good capacity retention of 78 %, which exhibits good rate capability at the current densities up to 3350 mA g(-1) as well.