Zwitterionic Polymer\nBinder Networks with Structural\nLocking and Ionic Regulation Functions for High Performance Silicon\nAnodes

The silicon anode suffers from significant volume expansion,\nlow\nelectrical conductivity, and poor long-term cycling performance, which\ncollectively limit its potential to replace graphite as the anode\nmaterial for lithium-ion batteries. In this article, a PAA-p(HEA-SBMA)\nbinder was prepared by an in situ thermal cross-linking method, which\ncombines strong mechanical properties and excellent reaction kinetics.\nThe synergy of covalent bonding, dynamic hydrogen bonding, and ionic\ninteractions in the binder structure provides excellent mechanical\nstrength, which effectively dissipates stresses and “locks”\nthe entire structure. In addition, the zwitterionic monomers in the\nbinder structure improve the transport of lithium-ions and promote\nlithium salt dissociation, which helps to establish a stable solid\nelectrolyte interphase (SEI). Thanks to the structural locking mechanism\nand dynamic ionic regulation function, the PAA-p(HEA-SBMA) binder\nexhibited a long cycling performance. Even after 1000 cycles at 0.5\nC, it still has a discharge capacity of 981.63 mAh g<sup>–1</sup>. The multifunctional binder designs in this work provide insights\ninto the advancement of high energy density lithium-ion batteries.