Constructing Robust Cross-Linked Binder Networks for Silicon Anodes with Improved Lithium Storage Performance

Abstract

Despite the high specific capacity of silicon as a promising anode material for the next-generation high-capacity Li-ion batteries (LIBs), its practical applications are impeded by the rapid capacity decay during cycling. To tackle the issue, herein, a bindergrafting strategy is proposed to construct a covalently cross-linked binder [carboxymethyl cellulose/phytic acid (CMC/PA)], which builds a robust branched network with more contact points, allowing stronger bonds with Si nanoparticles by hydrogen bonding. Benefitting from the enhanced mechanical reliability, the resulting Si-CMC/PA electrodes exhibit a high reversible capacity with improved long-term cycling stability. Moreover, an assembled full cell consisting of the as-obtained Si-CMC/PA anode and commercial LiFePO 4 cathode also exhibits excellent cycling performance (120.4 mA h g −1 at 1 C for over 100 cycles with 88.4% capacity retention). In situ transmission electron microscopy was employed to visualize the binding effect of CMC/PA, which, unlike the conventional CMC binder, can effectively prevent the lithiated Si anodes from cracking. Furthermore, the combined ex situ microscopy and X-ray photoelectron spectroscopy analysis unveils the origin of the superior Li-ion storage performance of the Si-CMC/PA electrode, which arises from its excellent structural integrity and the stabilized solid−electrolyte interphase films during cycling. This work presents a facile and efficient binder-engineering strategy for significantly improving the performance of Si anodes for next-generation LIBs.

Vanadium-Tailored Silicon Composite with Furthered Ion Diffusion Behaviors for Longevity Lithium-Ion Storage

“…The lattice spacing of the V-Si@C-1 composite is measured to be 0.314 nm, larger than that of the Si@C composite (0.313 nm, Figure S6a), which refers to the crystal plane of Si(111). 35 These results are consistent with our experimental design and shows that V doping can indeed significantly expand the lattice spacing of Si. In addition, the crystal planes of Si(311) and Si(220) can also be easily found by selected area electron diffraction (SAED) shown in Figure S6b.…”

Integrating Dually Encapsulated Si Architecture and Dense Structural Engineering for Ultrahigh Volumetric and Areal Capacity of Lithium Storage

“…After full lithiation (Figure 6K), the lattice spacing of 0.33 nm was observed, which can be ascribed to the (310) plane of Li 15 Si 4 (PDF# mp-569849), and the SAED pattern in the inset of Figure 6K 1 clearly confirmed the (310) and (321) planes of Li 15 Si 4 . 53,54 After full delithiation (Figure 6L), 0.31 nm lattice spacing was observed, which matched well with the standard card of Si (111) plane (PDF #27-1402). And the SAED pattern in Figure 6L 1 corresponds to the (111) and (220) crystal planes of Si.…”

An Elastic Cross-Linked Binder for Silicon Anodes in Lithium-Ion Batteries with a High Mass Loading

“…Besides, the SEI layer of the Si anode has a higher LiF content and lower Li x PF y content by using the PAA/Lys binder. The former plays a vital role in building a high-quality SEI layer for stable cycling of the Si anode, and the latter is from the decomposition of the Li salts. , These results imply that the use of the PAA/Lys binder can reduce the exposure of Si particles to the electrolyte by building a stable SEI layer.…”

“…Due to this fact, some binders with a cross-linking structure, such as polyrotaxane-polyacrylic acid (PR-PAA), alginate-calcium ions (Alg-Ca), and peach gum-epichlorohydrin (PG-c-ECH), exhibited an impressive binding ability. Therefore, developing 3D cross-linked binders is a promising solution to the challenges of Si anodes. − …”