Structure-function dual-track synergy in hyperbranched polymers: Topological mesh and polyhydroxy confinement for ultrastable aqueous zinc ion batteries

Parasitic reactions from highly reactive water molecules and uncontrolled zinc dendrite formation significantly obstruct the actual implementation of aqueous zinc-ion batteries (AZIBs). Traditional research on electrolyte additives frequently neglects the critical importance of particular molecular structures. This work presents a unique technique for electrolyte regulation guided by molecular architecture, which synergistically creates a physicochemical dual-barrier through topologically branching structures and localized multifunctional groups. Hyperbranched poly-α-glucoside (HPG), characterized by its multi-branched structure, is chosen as a multifunctional additive for proof of concept. HPG efficiently alters the internal interfacial milieu by fundamentally reorganizing the original solvation sheath, while its extensively branching structure facilitates the uniform deposition of Zn 2+ onto the electrode surface. Simultaneously, its many polyhydroxy functional groups are fully employed to reorganize the intermolecular hydrogen bond network of water. This synergistic approach accelerates the slow interfacial reaction kinetics and dramatically reduces water activity, effectively mitigating parasitic reactions and dendrite growth, and substantially augmenting the low-temperature tolerance of AZIBs. This modification technique enables Zn//Zn symmetric cells to exhibit an extraordinary cycle lifespan of 6000 h at 1 mA cm −2 and 1 mAh cm −2 , even maintaining an exceptional cycling endurance of 1600 h at sub-zero temperatures. Moreover, Zn//Cu asymmetric cells sustain a Coulombic efficiency of 99.93% throughout 2000 cycles, whereas Zn//NH 4 V 4 O 10 complete cells demonstrate a capacity retention of 74.2% at a high rate of 5 A g −1 . This novel electrolyte engineering approach paves the way for the advancement of high-performance, economical, and eco-friendly AZIBs.