Moderate yet Reversible Oligozwitterion Adsorption Unlocks Stable Zinc‐Ion Batteries

Abstract The practical application of aqueous zinc‐ion batteries (AZIBs) is mainly impeded by their limited lifespans due to rampant dendrite growth and parasitic side reactions on the electrode/electrolyte interface. Herein, a zwitterionic oligomer strategy is proposed to enable highly stable AZIBs by introducing oligo(propylsulfonate dimethylammonium propylmethacrylamide) (OPDP) into electrolyte as an additive. The strong interactions between OPDP and water/ions eliminate the water‐involved side reactions and promote ion migration both in the electrolyte and across the interface. More importantly, compared to the thick and irreversible sorption of the polyzwitterion counterpart on the anode, the regulated and reversible adsorption behavior of OPDP ensures the uniform deposition of Zn during plating, and meanwhile facilitates the stripping process. As a result, Zn//Zn batteries deliver a remarkable lifespan of over 4000 h at 1 mA cm −2 , and further display a stable cycling performance for more than 700 h under an ultra‐high depth of discharge of 54.7%. Moreover, the full AZIBs with polyaniline cathodes exhibit an improved Zn 2+ transport and storage kinetics, delivering an excellent cycling stability with a high capacity retention of 88% over 3000 cycles. This work provides an updated viewpoint on the functional additives for constructing uniform and adaptive interfaces to realize long‐life AZIBs.