Unveiling the Working Mechanism of Graphene Bubble Film/Silicon Composite Anodes in Li-Ion Batteries: From Experiment to Modeling

Abstract

In spite of the fact that there are plenty of recent studies on Si/graphene composite anodes, the influence of graphene on Li diffusion at the interface and lithiation associated mechanical behavior have not been well-understood. Furthermore, it is still a technical challenge to maintain a high capacity and an ultralong cycle life with high mass loading. Using a simple self-assembly approach, we have developed an all-integrated architecture of Si nanoparticles (SiNPs) encapsulated inside reduced graphene oxide (rGO) bubble films anchored in a 3D rGO macroporous network (encapsulated Si@rGO) as an anode for Li-ion batteries (LIBs). The enhanced electrochemical performance and structural stability of the anode are accomplished by the unique multifunctional rGO bubble film, which smoothly wraps SiNPs with notable void spaces. Its residual functional groups covalently bind with SiNPs, preventing their detachment from the electrode. The bubble wrap together with the outermost 3D framework accommodate the volume change, contributing to a stabilized solid electrolyte interphase (SEI) layer while maintaining ionic and electronic conductive pathways. Density functional theory (DFT) simulations show that the graphene coating boosts the mobility of the Li atoms at the Si–graphene interface. Molecular dynamics (MD) simulations confirm that graphene bubble film can effectively control the stress build-up near the Si surface, maintaining the structural integrity of the anode. The encapsulated Si@rGO anode with a mass loading of 2.6 mg cm–2 demonstrates exceptional cycling stability and superior rate capabilities. The anode demonstrates a high reversible capacity of 1346 mAh g–1 after 200 cycles at 500 mA g–1. Even at a high current density of 2.5 A g–1, a reversible capacity of 998 mAh g–1 is maintained after 1000 cycles with a capacity retention of 97%.

Amylopectin from Glutinous Rice as a Sustainable Binder for High‐Performance Silicon Anodes

“…Typically, the high-frequency semicircle corresponds to the charge transfer resistance (R), and the inclined straight line at the low-frequency represents Warburg impedance (W). [38][39][40] The Si-AP electrode exhibits significantly reduced charge transfer resistance than that with CMC and PVDF binder after 10 cycles. Such result indicates that the cross-linked structure of amylopectin binder can efficiently promote the transfer of electrons and Li + ions.…”

Multifunctional, Bioinspired, and Moisture Responsive Graphene Oxide/Tapioca Starch Nanocomposites

“…[ 31 ] The synthesis process of GO and its characterization are in correspondence with our previous studies. [ 32,33 ]…”

Theoretical Study of a New Porous 2D Silicon-Filled Composite Based on Graphene and Single-Walled Carbon Nanotubes for Lithium-Ion Batteries

“…The modified ReaxFF force field [39] allowedto describe the mechanism of Li ions interaction in ideal and defective carbon materials. Also, simulation of the lithiation process of Si and Si-C materials by the modified ReaxFF force field made possible the design of the new anode material with the capacity of 1345 mAh•g −1 [40]. The application of this force field was caused by the large number of atoms in the supercell and by the necessity in molecular dynamics.…”