Multifunctional Self-Cross-Linked Copolymer Binder for High-Loading Silicon Anodes

Abstract

Due to its ultra-high capacity and moderately low potential, silicon (Si) shows potential in replacing graphite-based anodes. Unfortunately, Si suffers from severe intrinsic volume expansions that restrict its practical use. Herein, we present a tailored copolymer, poly­(acrylamide)-co-poly­(hydroxymethylacrylate), p­(AM-co-HMA), as a multifunctional binder for Si anodes, which forms a 3D network structure via a thermally induced self-cross-linking reaction. The formed cross-linked binder structure provides both covalent and hydrogen bonds and thereby improves both the adhesion between the individual electrode components and the current collector as well as the adhesion between the individual Si particles. Overall, the p­(AM-co-HMA)-based binder offers superior electrochemical performance for high-loading Si anodes compared to traditionally applied binder systems.

Rational Design of High‐Loading Electrodes with Superior Performances Toward Practical Application for Energy Storage Devices

“…To address this issue, the development of functional binders has emerged as a promising approach to improve the sluggish kinetics of high-loading electrodes, particularly in cases with significant volume expansion, such as silicon anodes. [201][202][203][204] Functional binders leverage interchain entanglement to enhance mechanical strength and preserve the physical integrity of high-loading electrodes, effectively mitigating volume expansion. [202,204] Additionally, certain novel binders exhibit excellent conductivity and resist agglomeration, facilitating the formation of conductive pathways among active materials.…”

Intelligent Stress‐Adaptive Binder Enabled by Shear‐Thickening Property for Silicon Electrodes of Lithium‐Ion Batteries

“…The discharge capacities of the Si electrodes were monitored for up to 500 cycles to evaluate their long-term cycling stabilities. Notably, a 1 C-rate was maintained during the long-term charge-discharge tests, higher than the rates typically used in various other studies, which often range from 0.05 C to 0.5 C. [98][99][100] As shown in Figure 6g, the Si@AMLAP electrode maintained a significant fraction of its initial discharge capacity of 2025 mAh g −1 after 100 cycles. In contrast, the Si@AMSAP showed a low capacity and Si@SAP exhibited a clear capacity decline, retaining only 1647 and 467 mAh g −1 over 100 cycles, respectively (Figures S12 and S13, Supporting Information).…”

Multidimensional Branched Composite Binder via Covalent Grafting for High-Performance Silicon-Based Anodes

“…In addition, the elemental mapping spectra clearly show that Si particles mainly contain Si elements and a small amount of oxygen elements, indicating that the Si particles have an oxide layer on the surface. Whether it is the oxide layer or hydroxyl group on the Si surface, their existence is conducive to the hydrogen bond or covalent bond between Si and the polar group of the binder. ,, …”

“…Whether it is the oxide layer or hydroxyl group on the Si surface, their existence is conducive to the hydrogen bond or covalent bond between Si and the polar group of the binder. 48,55,56 To further explore the interface binding between the CA-g-PAA binder and Si, we conducted FTIR and XPS tests on the PAA/Si and CA-g-PAA/Si electrodes, respectively. After reacting with Si, a peak appears at 1707 cm −1 of the CA-g-PAA/Si electrode compared with the PAA/Si electrode (Figure S5), which can be speculated that the condensation reaction may occur between CA-g-PAA and Si.…”