• Energy Research

Aqueous zinc batteries are emerging technologies for energy storage, owing to their high safety, high energy, and low cost. Among them, the development of low-cost and long-cycling cathode materials is of crucial importance. Currently, Zn-ion cathodes are heavily centered on metal-based inorganic materials and carbon-based organic materials; however, the metal–organic compounds remain largely overlooked. Herein, we report the electrochemical performance of metal phthalocyanines, a large group of underexplored compounds, as alternative cathode materials for aqueous zinc batteries. We discover that the selection of transition metal plays a vital role in affecting the electrochemical properties. Among them, iron phthalocyanine exhibits the most promising performance, with a reasonable capacity (~60 mAh g−1), a feasible voltage (~1.1 V), and the longest cycling (550 cycles). The optimal performance partly results from the utilization of zinc chloride “water-in-salt” electrolyte, which effectively mitigates material dissolution and enhances battery performance. Consequently, iron phthalocyanine holds promise as an inexpensive and cycle-stable cathode for aqueous zinc batteries.

Aqueous zinc batteries are emerging technologies for energy storage, owing to their high safety, high energy, and low cost. Among them, the development of low-cost and long-cycling cathode materials is of crucial importance. Currently, Zn-ion cathodes are heavily centered on metal-based inorganic materials and carbon-based organic materials; however, the metal–organic compounds remain largely overlooked. Herein, we report the electrochemical performance of metal phthalocyanines, a large group of underexplored compounds, as alternative cathode materials for aqueous zinc batteries. We discover that the selection of transition metal plays a vital role in affecting the electrochemical properties. Among them, iron phthalocyanine exhibits the most promising performance, with a reasonable capacity (~60 mAh g−1), a feasible voltage (~1.1 V), and the longest cycling (550 cycles). The optimal performance partly results from the utilization of zinc chloride “water-in-salt” electrolyte, which effectively mitigates material dissolution and enhances battery performance. Consequently, iron phthalocyanine holds promise as an inexpensive and cycle-stable cathode for aqueous zinc batteries.