Tunicate-inspired versatile binder for silicon/graphite anodes enabled by co-operation of p-p stacking and hydrogen bonding interactions

Co-utilization of silicon (Si) and graphite (Gr) has become a commer-cially viable route to achieve higher energy density before the real-ization of pure Si anodes. However, the challenges of poor disper-sion in the aqueous binder and structural stability faced with Si/Gr remain difficult to negotiate. Herein, inspired by the outstanding adhesive ability of pyrogallol-containing proteins in tunicates, a wa-ter-soluble binder polyvinyl alcohol-gallic acid (PVA-GA) is synthe-sized via a one-step esterification reaction. Multiple supramolecular interactions of p -p stacking and hydrogen bonding are introduced to favor the homogeneous distribution of Si/Gr and the excellent structural stability of Si/Gr electrodes. The Si/Gr-PVA-GA delivers a high specific capacity of 568.6 mAh g-1 over 200 cycles, corre-sponding to 91.5% capacity retention and 0.038% capacity loss per cycle. Furthermore, the good practicality is demonstrated by the stable and safe operation of a Si/GrIILiNi0.6Mn0.2Co0.2O2 full cell with a practical level of areal capacity up to 3 mAh cm -2.