Polymer Binders Constructed through Dynamic Noncovalent Bonds for High‐Capacity Silicon‐Based Anodes

Abstract

Silicon (Si) is a promising candidate for high‐capacity anode materials owing to its high theoretical capacity (3579 mAh g−1), low working voltage, and wide natural abundance, although its huge volume variation during charge/discharge processes always results in a short cycling life. Polymer binders play a vital role in improving the cycling performance of Si‐based anodes, although traditional polyvinylidene difluoride cannot fulfil the requirements owing to its weak van der Waals forces with the Si surface. Recently, polymer binders constructed by dynamic bonds have been developed, which are reported to allow high‐energy‐density electrodes with improved electrochemical performance. With dynamic bonds including hydrogen bonding, ionic bonding, and host–guest interactions, these polymer binders possess self‐healing capabilities and enhanced mechanical performance, achieving a tremendous advance in addressing the capacity fading of Si‐based anodes. In this review, we will summarize the research progress of polymer binders constructed with dynamic bonds, and the challenges for their real applications in advanced Li‐ion batteries will also be discussed.

Key Factors for Binders to Enhance the Electrochemical Performance of Silicon Anodes through Molecular Design

“…Most of reviews on binders are mainly reported from the perspective of the type, [33] properties, [34] structure, [35] and dynamic bonds. [36] In addition, although there are some studies concerning the influence of interfacial bonding force, molecular structure and other factors on the performance of binders, there is still a lack of systematic and comprehensive discussions on the key factors affecting the performance of binders.…”

Viscoelastic properties and self‐healing behavior in a family of supramolecular ionic blends from silicone functional oligomers

“…32 Self-healing polymers based on ionic interactions can find applications in many fields such as the development of artificial e-skin devices, 32 microfluidic, therapeutic, 31 anti-fouling coatings, 33 and high-capacity Si-electrodes. 34 Among telechelic oligomers with ionic (acid-base) interactions, 23,24 Indeed, in the case of hydroxyl-terminated PDMS, they showed an increase in the T g value due to a decrease in the chain length. 24 This behavior, in contrast with results obtained with hydroxyl-terminated poly(propylene glycol), (PPG), was observed also in the case of amino-terminated and carboxylic-terminated telechelic PDMS, 23 and other low Tg polymers with polar end groups.…”

“…In case just ionic interactions are present in the network, either two oppositely charged ions or ions and induced‐dipole functions are involved, such as in telechelic oligomers terminated with acid and amine groups, 27,28 self‐healing poly(ethylene‐co‐methacrylic acid) based‐ionomers, 29,30 zwitterionic polymers, 31 polyelectrolyte complexes, and polymers with metal ion interactions 32 . Self‐healing polymers based on ionic interactions can find applications in many fields such as the development of artificial e‐skin devices, 32 microfluidic, therapeutic, 31 anti‐fouling coatings, 33 and high‐capacity Si‐electrodes 34 …”

Gradient H‐Bonding Binder Enables Stable High‐Areal‐Capacity Si‐Based Anodes in Pouch Cells

“…Therefore, such binders are not applicable for electrode manufacturing. [31] Recently, physically crosslinked polymers [32][33][34][35] have been reported as binders, exhibiting selfhealing and being deformable. These high-strain polymers are not only capable of effectively accommodating and enduring the volume change, but releasing local stress through chains slip and physically sacrificial interactions facture, thus reducing the destruction of electrodes.…”