Dual-Network Topology Engineering via Dynamic Cross-Linking for Advanced Cathode Binders

Binders are essential functional components in lithium-ion battery electrodes, functioning as a bridge that connects active materials, conductive additives, and current collectors. In response to the escalating global regulatory pressures on per- and polyfluoroalkyl substances, the development of nonfluorinated binders has become an urgent industrial need. In this study, we designed and synthesized a fluorine-free copolymer binder (AMIS) featuring dual polar functional groups (carboxyl and sulfonate) via multicomponent copolymerization, and following a cross-linking strategy by thiourea or thiohydantoin, which served as a hydrogen-bond donor-acceptor and facilitated the formation of a topological hydrogen-bond network within the binder. Electrochemical evaluation of electrodes utilizing the C-AMIS binder demonstrated a capacity retention of 86.96% over 200 cycles at 1 C and a rate capability of 61.90% at 5 C. These enhanced electrochemical properties are attributed to the synergistic stabilization provided by a dual hydrogen-bond-covalent-bond network, which effectively modulates interfacial stability, as well as battery performance. The dynamic bonding strategy proposed in this study is expected to inspire further structural design of environmentally friendly high-performance binders.