Nanosilica/carbon composite spheres as anodes in Li-ion batteries with excellent cycle stability

Abstract

10Because of high capacity, relatively low operation potentials, abundance and environmental 11 benevolence, silica presents a promising anode material for high-energy lithium-ion batteries. 12 In this work, to enhance the conductivity of silica and ensure robust connection between 13 silica particles and the host structure in the anode, nanosilica/carbon composite spheres have 14 been fabricated via the in-situ copolymerization of formaldehyde and resorcinol on the 15 surface of nanosilica particles, followed by a carbonization in an inert atmosphere. The 16 electrochemical properties of the as-prepared composite as an anode for lithium-ion batteries 17 are evaluated. When cycled at a current density of 100 mA g -1 with a voltage window of 18 0.0-3.0 V and calculated on the total mass of nanosilica and carbon, the nanosilica/carbon 19 composite spheres presents a stable capacity of about 620 mAh g −1 and the capacity retention 20 is nearly 100% after 300 cycles. Moreover, at different current densities, the as-prepared 21 composite exhibits high capacity and excellent cycle stability. The good electrochemical 22 2 performance is attributed to the relatively small volume variation of silica nanoparticles, 1 existence of pores/voids in the composite and robust connection between silica nanoparticles 2 and carbon matrix. 3 Keywords 4 Nanosilica/carbon composite; Spheres; Anode; Lithium ion battery; Electrochemical 5 performance 6 7

Amorphous-silicon@silicon oxide/chromium/carbon as an anode for lithium-ion batteries with excellent cyclic stability

“…5 is the cycle voltammetry curves of the a-Si@SiO x /Cr/C and a-Si@SiO x /Cr. In the first cycle, the a-Si@SiO x /Cr/C presents two reduction peaks at about 1.3 V and 0.8 V. Our previous study has confirmed that the two peaks correspond to the decomposition of electrolyte and the formation of SEI film [32]. The former is attributed to the reduction or decomposition of FEC, while the latter comes from that of other solvents like VC and EC.…”

Fabrication of graphene nanoplatelets-supported SiOx-disordered carbon composite and its application in lithium-ion batteries

“…Finally, the voltage platform of lithium insertion for the SiO x -C/GNPs is higher than those of graphite, which contributes to avoiding the formation For the SiO x -C/GNPs, two broad reduction peaks at about 1.35 V and 0.70 V in the first cycle, which disappear from the second cycle, are associated with the electrolyte decomposition and the formation of the solid electrolyte interface (SEI) layer. The former corresponds to the decomposition of FEC, while the latter is ascribed to the decomposition of other solvents in the electrolyte [41]. Both contribute to the irreversible capacity of the first discharge process.…”

Two-step ball-milling synthesis of a Si/SiOx/C composite electrode for lithium ion batteries with excellent long-term cycling stability

“…The peak at 1.46 V is associated with the electrolyte decomposition and the formation of the solid electrolyte interface (SEI) layer. 37 The broad peak at 0.34 V corresponds to the reduction reactions of SiO x , while the broad anodic peaks at 0.38 and 0.52 V correspond to the dealloying process of Li x Si and a part of Li 2 Si 2 O 5 , 38,39 attributing to the delithiation of Li x Si back to amorphous Si.…”