Facile and Efficient Fabrication of Branched Si@C Anode with Superior Electrochemical Performance in LIBs

Abstract

One‐dimensional Si nanostructures with carbon coating (1D Si@C) show great potential in lithium ion batteries (LIBs) due to small volume expansion and efficient electron transport. However, 1D Si@C anode with large area capacity still suffers from limited cycling stability. Herein, a novel branched Si architecture is fabricated through laser processing and dealloying. The branched Si, composed of both primary and interspaced secondary dendrites with diameters under 100 nm, leads to improved area capacity and cycling stability. By coating a carbon layer, the branched Si@C anode shows gravimetric capacity of 3059 mAh g−1 (1.14 mAh cm−2). At a higher rate of 3 C, the capacity is 813 mAh g−1, which retained 759 mAh g−1 after 1000 cycles at 1 C. The area capacity is further improved to 1.93 mAh cm−2 and remained over 92% after 100 cycles with a mass loading of 0.78 mg cm−2. Furthermore, the full‐cell configuration exhibits energy density of 405 Wh kg−1 and capacity retention of 91% after 200 cycles. The present study demonstrates that laser‐produced dendritic microstructure plays a critical role in the fabrication of the branched Si and the proposed method provides new insights into the fabrication of Si nanostructures with facility and efficiency.

Core–Shell Structured C@SiO2 Hollow Spheres Decorated with Nickel Nanoparticles as Anode Materials for Lithium‐Ion Batteries

“…[21][22][23][24] Unfortunately, the serious volume expansion of silicon (>300%) in the process of lithiation accompanied by structural fracture and pulverization limits its practical application. [25][26][27][28][29] Although massive efforts have been put in solving this issue, silicon anodes have not yet been broadly commercialized because of the costly and complex preparation. Well ahead of time, silica was considered to be electrochemically inactive toward lithium because of the low ion diffusivity and the electronic insulation.…”

Pomegranate-type Si/C anode with SiC taped, well-dispersed tiny Si particles for lithium-ion batteries

“…From Fig. S7 in the ESM, a pomegranate-type framework can be seen clearly, suggesting that the structure can be destroyed by cycling, and the rougher surface compared with SEM image before cycling is due to uniform SEI film formed on the material surface [44]. The intact structure inhibits the continuous electrolyte deposition and ensures the uniform formation of SEI film.…”

Carbon Yarn‐Ball‐Entangled SiO2 Anode with Excellent Electrochemical Performance for Lithium‐Ion Batteries

“…[4,7] Conductive matrices such as graphene and carbon nanotubes can effectively buffer the collective volume expansions of dispersed nanoscale SiO 2 particles; however, sophisticated procedures are usually required to prepare the matrix and composite nanoscale SiO 2 . [3,39] From the perspective of real production, the coalesced micrometer-sized secondary particles, rather than dispersed nanoparticles, are more favorable for achieving higher energy density and are easier to adapt to the current electrode fabrication process. [1,5,6,35,40] Recently, pomegranate-like structure, 2D carbon sheet wrapped structure, and watermelon-like structure have been developed to compactly coalesce individual Si nanoparticles [5,41] and have shown great potential for real applications.…”

“…Third, the tap density of the micrometer-sized SiO 2 @CYB is approximately 1.15 g cm −3 , which is much higher than that of dispersed nanoscale SiO 2 ; this is very attractive for high-energy density batteries. [3,33,42] The XRD profiles of SiO 2 @CYB, SiO 2 /C, and pristine SiO 2 are compared in Figure 3a. The large hump (≈24°) is characteristic of amorphous SiO 2 .…”

“…The demand for achieving performance parity between electric vehicles and internal combustion engine vehicles has greatly stimulated the exploration of advanced electrode materials for high-energy-density lithium-ion batteries. [1][2][3][4] In the search for novel anode materials, Si has drawn much attention owing to its large theoretical specific capacity of 4200 mAh g −1 ; however, its drastic lattice volume expansion of nearly 400% has hindered its application. [5][6][7][8][9] Amorphous SiO 2 is considered a promising alternative for Si anodes owing to its large theoretical capacity of 1965 mAh g −1 , far beyond the conventional carbonaceous anode, and a lithiation-caused lattice volume expansion milder than that of Si.…”