Asymmetric Electrolytes Govern Tetrahydroxozincate Dynamics for Stable Alkaline Zinc Batteries

Abstract

ABSTRACT Green electrochemical energy storage is essential for carbon neutrality, and alkaline zinc batteries offer a compelling solution due to their inherent safety, low cost, and high energy density. However, their performance is limited by parasitic reactions, including corrosion, gas evolution, and slow Zn/ZnO conversion kinetics stemming from inefficient dissociation of the tetrahydroxozincate [Zn(OH) 4 2− ] intermediate. We address this by designing a series of cobalt porphyrins (Co‐4N, Co‐3N‐O, Co‐3N‐S) that modulate the metal center's charge density for accelerating Zn(OH) 4 2 − decomposition, and control Zn 2 + transport through the carboxyl‐functionalized peripheries. The Co‐3N‐O‐modified electrolyte achieves exceptional stability, maintaining stable cycle for over 80,000 s at 5 mA cm − 2 , which is more than four times longer than the <20,000 s achieved by the conventional KOH + ZnO electrolyte. In Zn||Ni batteries, this molecularly engineered electrolyte enables 110 stable cycles at 1 mA cm −2 , significantly outperforming the unmodified system, which sustained only 20 cycles. These findings elucidate a structure‐kinetics relationship for zincate regulation and demonstrate how customized molecular asymmetry can overcome persistent challenges in aqueous battery chemistry, offering a pathway to high‐performance, durable energy storage systems.