Porous Si@SiO_x@N‐Rich Carbon Nanofibers as Anode in Lithium‐Ion Batteries under High Temperature

Abstract

A facile electrospinning technique followed by pre‐oxidation and carbonization treatment is adopted to synthesize silicon anode cladded with SiOx layer and N‐rich carbon nanofibers (Si@SiOx@NCNFs), in which post‐used polyacrylonitrile (PAN) yarn is chosen as single carbon source. As anode in Li‐ion batteries, elaborately designed Si@SiOx@NCNFs renders remarkable reversible capacities of 1045 mA h g−1 at the 500th cycle under a current density of 8 A g−1 at 80°C, and 828 mA h g−1 after subsequent 500 cycles at 15 A g−1, mainly ascribed to the distinct hierarchical structure, N‐rich nature and enhanced pesudocapacitive behavior. When Si@SiOx@NCNFs is matched with commercial cathode LiFePO4, full cell delivers a stable capacity of 140 mA h g−1 at 100 mA g−1, accompanying with an energy density of 455 Wh kg−1 at 50 °C. These conspicuous features undoubtedly enable Si@SiOx@NCNFs to be promising anode materials for high‐power lithium‐ion battery used in harsh conditions.

Si/FeSi2 Nanoparticles Prepared by Thermal Plasma with Stress‐releasing Effect for Li‐ion Storage

“…Especially, the peak observed only in the first cycle with gentle slope from 0.2 to 0.8 V is ascribed to the original formation of the SEI layers on the materials. However, this peak disappeared in the subsequent four cycles, revealing that stable SEI layers was formed on the surface of the electrode [61] . All these typical peaks in the CV curves are compliant with the plateau on the voltage‐capacity curves, which is displayed in Figure S10.…”

“…In Nyquist plots, a semicircle in high‐frequency region represents charge transfer resistance (R ct ) and the R e (solution resistance) represents the Li + migrate through the electrolyte into the electrode surface. Besides, the R SEI represents the resistance of lithium ions entering the SEI layers [27,29,61] . There is a sloping line in low‐frequency region called Warburg resistance, which represents the lithium‐ion finally diffuse into the interspace of the electrode materials [64,65] .…”

Si/SiOx Nanoparticles Embedded in a Conductive and Durable Carbon Nanoflake Matrix as an Efficient Anode for Lithium‐Ion Batteries

“…The high‐resolution Si 2p spectrum in Figure S2(d) shows the peaks at binding energies of 99.5 and 104 eV, corresponding to Si and SiO 2, respectively. The peaks in the binding energy range of 99–105 eV represent the data for SiO x (0 ), indicating the successful formation of the SiO x layer on the surfaces of Si NPs …”

“…The peaks in the binding energy range of 99-105 eV represent the data for SiO x (0< x < 2), indicating the successful formation of the SiO x layer on the surfaces of Si NPs. [42] SEM and TEM were used to determine the morphologies and structures of the prepared samples. The SEM images of SEC105 (Figure 3a shows that this carbon is not in contact with the surfaces of the Si@SiO x NPs, and the amount of carbon is very low, which can be a reason for its absence in the TGA curves.…”

A Low-Cost and High-Capacity SiOx/C@graphite Hybrid as an Advanced Anode for High-Power Lithium-Ion Batteries

“…The fresh active site could provide more sites to store charge, thereby increasing capacity. 34 The subsequent growth of capacity is ascribed to the high rate lithiation-induced reactivation, which could effectively restructure the porous microstructures and optimize the stable SEI. 50 With the stable SEI formation and structure refinement, the reactivated anode materials showed a high capacity and excellent cycling performance even in a long cycle at a high rate.…”