A 1000 Wh Kg-1 Cathode Facilitated by In Situ Mineralized Electrolyte with Electron Potential Well for High-Energy Aqueous Zinc Batteries.

Abstract

The practical applications of aqueous zinc-ion batteries (AZMBs) are hindered by challenges such as low energy density and limited cycle life, which stem from the one-electron transfer at the cathode and dendrite formation at the anode. Herein, inspired by the biomineralization phenomenon in nature, an in situ mineralized electrolyte (IME) containing Prussian blue analogs (PBAs) as an electron potential well is designed. This in situ mineralization strategy promotes uniform, rapid, and reversible charge transfer at the electrode/electrolyte interfaces, enabling the Iodine (I₂) cathode to achieve a specific capacity of 286.4 mAh g⁻¹ at 1 A g⁻¹ and an energy density of 330.8 Wh kg⁻¹. Simultaneously, the potential well facilitates the in situ recovery of Zn dendrites into active Zn2⁺ ions, ensuring stable Zn anode cycling with a practical areal capacity of 5 mAh cm⁻2 for 1500 h. Furthermore, the mediation of iodine-bromine chemistry enables highly reversible Br⁰/Br⁻ and I⁺/I⁰/I⁻ reactions, achieving an energy density of more than 1000 Wh kg-1. Additionally, an enhanced energy density of 503 Wh kg⁻1 and a high energy efficiency of 86.73% over 6000 cycles are achieved. In summary, the in situ mineralization of an electron potential well in electrolyte offers a novel pathway for developing high-energy and long-lifespan AZMBs.