Tight Binding and Dual Encapsulation Enabled Stable Thick Silicon/Carbon Anode with Ultrahigh Volumetric Capacity for Lithium Storage

Abstract

Silicon (Si) is regarded as one of the most promising anode materials for high‐performance lithium‐ion batteries (LIBs). However, how to mitigate its poor intrinsic conductivity and the lithiation/delithiation‐induced large volume change and thus structural degradation of Si electrodes without compromising their energy density is critical for the practical application of Si in LIBs. Herein, an integration strategy is proposed for preparing a compact micron‐sized Si@G/CNF@NC composite with a tight binding and dual‐encapsulated architecture that can endow it with superior electrical conductivity and deformation resistance, contributing to excellent cycling stability and good rate performance in thick electrode. At an ultrahigh mass loading of 10.8 mg cm−2, the Si@G/CNF@NC electrode also presents a large initial areal capacity of 16.7 mA h cm−2 (volumetric capacity of 2197.7 mA h cm−3). When paired with LiNi0.95Co0.02Mn0.03O2, the pouch‐type full battery displays a highly competitive gravimetric (volumetric) energy density of ≈459.1 Wh kg−1 (≈1235.4 Wh L−1).

Design of Supported–Coated Structure Silicon/Carbon Composites Using Industrial Waste Micrometer-Sized Silicon for an Advanced Lithium-Ion Battery Anode

“…The patterns of Si with three typical characteristic peaks at 2θ = 28.4°, 47.4°, and 56.1° are assigned to the (111), (220), and (311) planes of crystalline Si [Joint Committee on Powder Diffraction Standards (JCPDS) 27-1402], respectively. Of note, the diffraction peaks of TNS and Si appear simultaneously in the Si/G@TNS-60 sample, and their intensities are weakened obviously, implying the TNS recombination and coating on Si . The Raman spectra of both TNS and Si/G@TNS-60 (Figure c) display three diffraction peaks at 290, 412, and 603 cm –1 , assigned to Ti–C bond vibrations. , Besides, the peak at 510 cm –1 corresponds to the Si–Si bond vibration, observed in both Si and Si/G@TNS-60. , Furthermore, the characteristic peaks at 1325 and 1575 cm –1 in Si/G@TNS-60 are related to the D band (defects carbon) and the G band (sp 2 -bonded graphitic carbon) of the graphite carrier used to anchor Si. − XPS was employed to provide a detailed characterization of the surface bonding and chemical state.…”

“…Of note, the diffraction peaks of TNS and Si appear simultaneously in the Si/G@TNS-60 sample, and their intensities are weakened obviously, implying the TNS recombination and coating on Si . The Raman spectra of both TNS and Si/G@TNS-60 (Figure c) display three diffraction peaks at 290, 412, and 603 cm –1 , assigned to Ti–C bond vibrations. , Besides, the peak at 510 cm –1 corresponds to the Si–Si bond vibration, observed in both Si and Si/G@TNS-60. , Furthermore, the characteristic peaks at 1325 and 1575 cm –1 in Si/G@TNS-60 are related to the D band (defects carbon) and the G band (sp 2 -bonded graphitic carbon) of the graphite carrier used to anchor Si. − XPS was employed to provide a detailed characterization of the surface bonding and chemical state. The full spectrum in Figure S2 and Table S1 of the Supporting Information verifies the coexistence of C, Si, and Ti elements in Si/G@TNS-60.…”

“…The XRD pattern of the Ti 3 AlC 2 powder is shown Si. 1 The Raman spectra of both TNS and Si/G@TNS-60 (Figure 1c) display three diffraction peaks at 290, 412, and 603 cm −1 , assigned to Ti−C bond vibrations. 29,40 Besides, the peak at 510 cm −1 corresponds to the Si−Si bond vibration, observed in both Si and Si/G@TNS-60.…”

“…29,40 Besides, the peak at 510 cm −1 corresponds to the Si−Si bond vibration, observed in both Si and Si/G@TNS-60. 1,41 Furthermore, the characteristic peaks at 1325 and 1575 cm −1 in Si/G@TNS-60 are related to the D band (defects carbon) and the G band (sp 2bonded graphitic carbon) of the graphite carrier used to anchor Si. It can be observed that the carbon content of Si/G@TNS-60 is about ∼21.6% (Figure S3 of the Supporting Information), and it can be estimated that the content of silicon is ∼50.4% based on the mass ratio of silicon/graphite.…”

“…In addressing the “three major anxieties” of electric vehicles (driving range, charging time, and use lifespan), it is urgent to develop lithium-ion batteries (LIBs) with high energy density, high-rate performance, and extended cycle life to meet growing demands. − However, the traditional anode of graphite has reached its theoretical capacity limit of 372 mAh g –1 , which is insufficient for advanced power batteries. − Silicon (Si) offers numerous advantages, such as ultrahigh capacity (4200 mAh g –1 ), low operating potential, and natural abundance, making it a highly promising candidate for the next generation of LIBs. Unfortunately, Si is plagued by significant volumetric fluctuations (300–400%) during the lithiation and delithiation processes, resulting in particle fragmentation, loss of electrical contact, and repeated reorganization and accumulation of solid electrolyte interfaces (SEIs).…”