Interface-Adaptive Binder Enabled by Supramolecular Interactions for High-Capacity Si/C Composite Anodes in Lithium-Ion Batteries

Abstract

Although Si and graphite (Si/C) composite materials are among the most promising alternative to graphite anode in commercial batteries because of high capacity, the issue of the poor structural and interfacial stability of the composite electrode is extremely challenging. Herein, an interface-adaptive triblock polymer binder that can interact Si and graphite particles to improve the particle affinity and binder spreadability via the supramolecular interactions of π∙∙∙π stacking and hydrogen bonding is presented. The strategy of enhancing the interfacial interactions can further effectively stabilize the electrode interface and minimize the electrode/electrolyte side reactions. Benefiting from this proposed binder, the Si/C anode retains a high reversible capacity (82.1%) after 400 cycles and delivers improved cycling stability even at high areal capacity (4 mAh cm⁻², 0.067% capacity loss/cycle) and in Si/C|LiNi_0.8Co_0.1Mn_0.1O₂ full cell (0.22% capacity loss/cycle). This design strategy for the binder provides a novel path toward high-energy, long-cycling Si/C anodes.