A Pyrene–Poly(acrylic acid)–Polyrotaxane Supramolecular Binder Network for High‐Performance Silicon Negative Electrodes

Although being incorporated in commercial lithium‐ion batteries for a while, the weight portion of silicon monoxide (SiO_x, x ≈ 1) is only less than 10 wt% due to the insufficient cycle life. Along this line, polymeric binders that can assist in maintaining the mechanical integrity and interfacial stability of SiO_x electrodes are desired to realize higher contents of SiO_x. Herein, a pyrene–poly(acrylic acid) (PAA)–polyrotaxane (PR) supramolecular network is reported as a polymeric binder for SiO_x with 100 wt%. The noncovalent functionalization of a carbon coating layer on the SiO_x is achieved by using a hydroxylated pyrene derivative via the π–π stacking interaction, which simultaneously enables hydrogen bonding interactions with the PR–PAA network through its hydroxyl moiety. Moreover, the PR's ring sliding while being crosslinked to PAA endows a high elasticity to the entire polymer network, effectively buffering the volume expansion of SiO_x and largely mitigating the electrode swelling. Based on these extraordinary physicochemical properties of the pyrene–PAA–PR supramolecular binder, the robust cycling of SiO_x electrodes is demonstrated at commercial levels of areal loading in both half‐cell and full‐cell configurations.