Strategy for Boosting Li-Ion Current in Silicon Nanoparticles

Abstract

Improvement in the rate capability needs to be addressed for utilization of a Si anode in high-power Li-ion batteries. Regarding the rate capability, its improvement by Si–C nanocomposites seems to be somewhat saturated, thus indicating that the other method should be tried for further enhancement of the rate capability. Here, we introduce Si nanoparticles uniformly coated with nanometer-thick polyacrylonitrile (PAN) with better wettability to liquid electrolytes and minimizing electronic resistance, which might result from a thick PAN coating: the effective contact surface area made by the contact of Si nanoparticles and liquid electrolyte is increased for larger Li-ion current, leading to ultrafast rate capability retaining 62% of the 0.2C rate discharge capacity at 100C. In addition, a strong adhesive property of PAN provides highly mechanically robust Si anodes for multielectrode-stacked flexible lithium-ion batteries, which show no physical damage after 30 000 bending cycles with a bending radius of 25 mm.

Catalytic Growth of Graphitic Carbon‐Coated Silicon as High‐Performance Anodes for Lithium Storage

“…To further elucidate the performance differences between p‐SiNSs and p‐SiNSs@C‐2 electrode, the contact angles were examined. As shown in Figure a,b, the contact angles of p‐SiNSs and p‐SiNSs@C‐2 electrodes are 21.9 and 8.6, which shows the p‐SiNSs@C‐2 electrode has better wetting of the electrolyte than p‐SiNSs . The morphology and thickness diversification are direct evidences to certificate the electrochemical performances of batteries.…”

Tubular Graphene Nano-Scroll Coated Silicon for High Rate Performance Lithium-Ion Battery

“…Peaks shown using X-ray photoelectron spectroscopy (XPS) could be attributed to carbon and silicon ( Figure 2D); the Si peaks are much lower than the peak of carbon because the silicon is completely wrapped by the graphene scroll. In the case of the high-resolution XPS spectra, C 1s (Figure 2E), peaks fitted at ∼284.1, ∼285.4, and ∼286.2 eV are successively assigned to graphene surface functional groups of C-C, C = C, and C-O, respectively (Song et al, 2018). For the XPS spectrum, Si 2p could be derived from two peaks located at 99.5 and 104 eV ( Figure 2F), which could be attributed to Si and SiO 2 , respectively (He et al, 2018).…”

“…As shown in Figures 5C,D, the Si@rGONSs-2 electrode after 100 cycles retains its original appearance with no crack or peel-off phenomenon (Xu et al, 2018). The contact angles of commercial Si and Si@rGONSs-2 electrode are 20.2 and 9.5 • , respectively (Figures S6A,B), which shows that the Si@rGONSs-2 electrode has better electrolyte wetting performance compared with commercial Si (Song et al, 2018). Better electrolyte wetting and the open tubular structure provides space to handle variation in volume; thus, the Si@rGONSs-2 electrode possesses outstanding stability and reversibility.…”

Extreme Rate Capability Cycling of Porous Silicon Composite Anodes for Lithium‐Ion Batteries

“…reported that their rate capability test on Si nanoparticles is up to 8C (8 A g −1 ) for 300 cycles [27] . Several rate capability tests have been reported on a silicon‐based half‐cells, but the tests were limited up to 150 cycles without considering extended cycling [28–32] …”