Magnetic Field‐Tailored Copper Layers With Fast Dissolution‐Redeposition Kinetics for Stable Zinc Metal Anodes

Chemical displacement offers a straightforward route to fabricate metal protective layers on zinc anodes. However, stochastic and inhomogeneous nucleation and growth of the displaced metal, together with uncontrollable dynamic evolution, often culminate in a limited protective effect. Herein, we propose a magnetic field‐assisted strategy to modulate displacement reaction kinetics, yielding a uniform and compact Cu protective layer on Zn (ZnCu‐MF). The magnetohydrodynamic effect governs Cu 2+ transport during displacement, promotes uniform Cu nucleation, and suppresses the “galvanic cell” dominated displacement pathway. Furthermore, we verify the interfacial reaction mechanisms involving copper dissolution‐redeposition and Zn‐Cu co‐deposition, which accelerate interfacial kinetics and foster the formation of a zincophilic CuZn 5 alloy layer, thereby enabling stable long‐term and high‐rate cycling. Consequently, ZnCu‐MF||ZnCu‐MF symmetric cells achieve a cycle life exceeding 5000 h at 2 mA cm −2 and over 4800 h at 10 mA cm −2 . Moreover, ZnCu‐MF||Cu half‐cells deliver an average coulombic efficiency of 99.8% over 1300 cycles. A full cell with a vanadium‐based cathode exhibits superior rate capability and a lifespan surpassing 1000 cycles. Remarkably, a pouch cell with high loading of 19.35 mg cm −2 (4.7 mAh cm −2 ) and a low N/P ratio of 3.7 attains about 0.3 Ah and sustains stable operation for over 300 cycles.