A synergistic dual-additive strategy inducing macromolecular disentanglement for highly stable zinc anodes

At present, electrolyte additives are considered one of the most effective optimization strategies for advanced electrolyte in aqueous zinc-ion batteries (AZIBs), However, promising polysaccharide polymer additives are trapped in a dual dilemma of "solubility versus functionality", strong intermolecular hydrogen-bond entanglement restricts their solubility at room temperature and hinders their multidimensional regulatory potential. To address this issue, we propose a synergistic modulation strategy based on "macromolecular disentanglement" and develop sodium alginate-manganese sulfate dual-additive modification strategy. Mn²⁺ ions act as molecular decoupling agents, precisely disrupting hydrogen-bond network of SA and inducing a transformation of the polymer chains from a tightly entangled state to a fully extended conformation, thereby fully unlocking their coordination-active sites. This conformational evolution achieves dual synergy of bulk solvation reconstruction and in-situ interfacial film formation, reducing free water activity in bulk electrolyte and inducing the formation of a robust "eggshell-like" SEI layer at the interface. Empowered by this multidimensional protection, symmetric cells achieve stable cycling for over 2400 h at a high current density of 10 mA cm^-2, while full-cell lifespans exceed 26,000 cycles at high rates. This study opens a universal new pathway for the rational design of high-performance electrolyte systems based on natural polymers.