Ampere‐Hour‐Scale Aqueous Nickel–Organic Batteries based on Phenazine Anode

Abstract Aqueous nickel‐based batteries, particularly nickel‐organic batteries, are promising candidates for large‐scale energy storage applications owing to their environmental friendliness, abundant resources, and intrinsic safety. However, organic anode materials suffer from serious dissolution in electrolytes during discharge/charge processes and ampere‐hour‐scale nickel‐organic batteries are still absent. Here, phenazine (PZ) is screened as the anode and utilizes 10 m KOH as the electrolyte to construct ampere‐hour‐scale PZ/Ni(OH)₂ batteries to demonstrate the practicability. In situ, UV–vis and molecular dynamics simulations demonstrate the inhibited dissolution of PZ in high‐concentration of 10 m KOH. The PZ anode can provide a high initial specific capacity of 281.6 mAh g⁻¹ at 0.5 C with a Coulombic efficiency of 98.6% and ultralong cycle life with a capacity retention of 74.3% after 14 000 cycles at 30 C. Moreover, the fabricated pouch‐type PZ/Ni(OH)₂ battery with a high PZ mass‐loading of 48 mg cm⁻² delivers a capacity of 1.23 Ah and achieves a high energy density of 50 Wh kg⁻¹ (based on the total mass of the cell). The abundant resources, excellent stability, and cost‐effectiveness of phenazine endow nickel‐organic batteries with promising potential for large‐scale energy storage applications.