Electrochemical Performance of an Ultrathin Surface Oxide-Modulated Nano-Si Anode Confined in a Graphite Matrix for Highly Reversible Lithium-Ion Batteries

Abstract

Si-based anode materials have attracted considerable attention for use in high-capacity lithium-ion batteries (LIBs), but their practical application is hindered by huge volume changes and structural instabilities that occur during lithiation/delithiation and low-conductivity. In this regard, we report a novel Si-nanocomposite by modulating the ultrathin surface oxide of nano-Si at a low temperature and highly conductive graphene–graphite matrix. The Si nanoparticles are synthesized by high-energy mechanical milling of micro-Si. The prepared Si/SiO x @C nanocomposite electrode delivers a high-discharge capacity of 1355 mAh g–1@300th cycle with an average Coulombic efficiency of 99.5% and a discharge capacity retention of ∼88% at 1C-rate (500 mA g–1). Remarkably, the nanocomposite exhibits a high initial Coulombic efficiency of ∼87% and excellent charge/discharge rate performance in the range of 0.5–5C. Moreover, a comparative investigation of the three different electrodes nano-Si, Si/SiO x , and Si/SiO x @C are presented. The exceptional electrochemical performance of Si/SiO x @C is owing to the nanosized silicon and ultrathin SiO x followed by a high-conductivity graphene–graphite matrix, since such a nanostructure is beneficial to suppress the volume changes of silicon, maintain the structural integrity, and enhance the charge transfer during cycling. The proposed nanocomposite and the synthesis method are novel, facile, and cost-effective. Consequently, the Si/SiO x @C nanocomposite can be a promising candidate for widespread application in next-generation LIB anodes.

Synthesis, Electrochemistry, and Thermal Stability of High‐Energy Ball‐Milled Silicon‐based Alloy Anodes in Lithium‐Ion Batteries**

“…[46] The fitting results imply that although the three samples have close R sei after the two cycles, R ct has an apparent reduction varying from 22.2 Ω in Si 96.3 (CuO) 3.7 to 6.4 Ω in Si 87.5 (CuO) 3.4 (NiO) 9.1 . The decreased impedance indicates that the ionic conductivity for the SiÀ CuOÀ NiO samples is improved, [47] which could be ascribed to the reduced volume change of Si-based particles rendering the more intact electrode, stable SEI, and better electrical contact. Therefore, combining the electrochemical tests, cross-section SEM images, and EIS analysis, we can conclude that adding NiO with a proper amount to the ball-milled SiÀ CuO samples could positively affect the electrochemical performance with further optimized capacity retention and ACE.…”

Ionic/Electronic Dual‐Conductor Coating Layer Fabrication Enabling High‐Performance Silicon Anode

“…The activation in the cycling process enables more Li + to be stored in the carbon shells and the pulverized Si particles of the Si@Li 4 SiO 4 /C/CNTs, which makes the capacity of the electrode stable and increase to some degree. [ 29 ] The prepared Si@Li 4 SiO 4 /C/CNTs anode shows excellent cycling stability compared with the previously reported Si‐based anodes for LIBs, [ 28–39 ] and a detailed comparison was prepared in Table S1, Supporting Information.…”

Si/CrSi2 Alloy Anodes Synthesized by a High-Energy Ball-Milling Method for Lithium-Ion Batteries: Microstructure, Electrochemistry, and Carbon Coating

“…More than that, the milder structural variation of the Si 85 Cr 15 @c-PDA electrode is also in favor of providing smooth reaction pathways and improving electronic/ionic transportation. 51 Hence, less R ct can be witnessed in Figure 10d for Si 85 Cr 15 @c-PDA, and it has been showing a downward trend. In contrast, not only the value of R ct in Figure 10c for mSi@c-PDA is higher, but also it nearly triples from the 50th cycle to the 100th cycle, most likely led by the mechanical failure and electrical disconnection derived from the repeatedly enormous volume evolution of the electrode.…”