Non‐Expendable Regulator Enables Durable and Deep Cycling Aqueous Zinc Batteries

Abstract Unstable electrode/electrolyte interface with irreversible Zn deposition and hydrogen reactions have severely damage the cycle life of aqueous zinc‐metal batteries (ZMBs), which is closely related to interfacial environment and deposition behavior of Zn 2+ . In this work, a series of rare earth chlorides (RCl 3 ) are proposed as non‐expendable regulators to address the above problems. Specifically, rare earth cations (R 3+ ) with high adsorption energy can simultaneously isolate the adsorbed polar H 2 O molecule layer at the anode interface and regulate uniform Zn deposition behavior by electrostatic shielding. Meanwhile, Cl − binds H 2 O molecules via the weak hydrogen bonds, thus further inhibiting water‐related side reactions. Consequently, the optimized Zn||Zn symmetric cell can stably cycle for over 8000 cycles at 5 mA cm −2 . Surprisingly, the Zn anode with 68.3% zinc utilization also can be operated over 130 h. Even under harsh condition of low N/P ratio of 2.6:1 and high mass‐loading cathode of 12.57 mg cm −2 , the NH 4 V 4 O 10 ||Zn pouch cell preserves nearly all its capacity after 300 cycles. Further, a low N/P ratio pouch cell with a more respectable capacity of 37.3 mAh preserves deep cycling for 180 cycles. This study sheds light on non‐expendable additives to develop highly durable and deep cycling ZMBs.