A currently commercialized graphitebased anode in LIBs cannot meet the increasing demand for high energy density because of the limited theoretical specific capacity of graphite (372 mAh g −1 ). [2] As an alternative to the graphite anode for highenergy anode materials, silicon has gained substantial attention due to its high theoretical specific capacity of 3579 mAh g −1 at room temperature (Li 15 Si 4 ), [3] low working potential (0.4 V vs Li + /Li), [4] nontoxicity, and natural abundance. [5] However, the massive volume change of Si (≈300%) during lithiation/delithiation processes causes various problems, including pulverization, delamination of electrodes, [6] and uncontrollable growth of the solidelectrolyte interface (SEI) layer, [7] resulting in a significant irreversible capacity and rapid capacity decay. [8] Furthermore, Si has low conductivity of ≈0.67 mS cm −1 , [9] leading to a relatively poor rate capability. To address aforementioned issues and enhance the cycle life of Si anodes, several approaches have been developed, including the design of nanostructured Si (porous, yolk-shell, nanowires, and nanomesh), [10][11][12] artificial SEI layer, [13] composites, [14,15] electrolytes, [16] and binders. [17,18] Proper design of binders is particularly crucial for Si anodes because binders affect the structural integrity and mechanical stability of Si anodes. Unfortunately, the most widely used polyvinylidene fluoride (PVDF) binder is unsuitable for Si anodes, showing fast capacity decay due to its insufficient mechanical properties and weak van der Waals interaction with Si. [19] Thus, other diverse polymeric binders have been explored, including poly(acrylic acid) (PAA), [20] sodium carboxymethoxy cellulose, [21] sodium alginate, [22] guar gum, [23] and other functionalized polymers for Si anodes. [24,25] These binders have polar functional groups interacting more closely with Si active materials, offering better adhesion and enhanced capacity retention compared with the PVDF binder. However, Si anodes with those binders were also gradually degraded over the repeated charge/discharge cycles because of the massive volume expansion of Si, resulting in significant capacity decay.A self-healing binder is especially desirable for Si anodes because of its capability to self-heal mechanical damages or cracks typically generated during cycling. For instance, selfhealing polymers with urea functional groups offer abundant hydrogen bonding sites and self-healing properties, which Despite of extremely high theoretical capacity of Si (3579 mAh g −1 ), Si anodes suffer from pulverization and delamination of the electrodes induced by large volume change during charge/discharge cycles. To address those issues, herein, self-healable and highly stretchable multifunctional binders, polydioxythiophene:polyacrylic acid:phytic acid (PEDOT:PAA: PA, PDPP) that provide Si anodes with self-healability and excellent structural integrity is designed. By utilizing the self-healing binder, Si anodes self-repair cracks and damages of...
