Metal Vacancies-Rich MBenes Catalytically Expedite Desolvation Kinetics for Highly Reversible Low-Temperature Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) hold significant promise for energy storage; however, the high dissociation energy barriers of bulky hydrated zinc ions ([Zn(H2O)6]2+) induce uneven Zn deposition, leading to severe capacity degradation and a limited cycle life. Herein, an effective desolvation-enhanced zinc anode protective layer is constructed using Mo4/3B2–X nanosheets, in which the etching-induced metal vacancies and –F zincophilic sites endow the layer with a strong affinity for Zn2+ and effectively catalyze the desolvation of [Zn(H2O)6]2+. Experimental and theoretical calculations demonstrate that under the action of Mo4/3B2–X, the desolvation energy of [Zn(H2O)6]2+ can be effectively reduced from 38.99 kJ mol–1 of bare Zn to 27.67 kJ mol–1, significantly promoting greater flux and rapid diffusion of free Zn2+. As a result, this configuration achieves a dendrite-free Mo4/3B2–X-Zn anode with an ultralong cycling life exceeding 2000 h, which is 18 times that of bare Zn. Even under low-temperature conditions at 0 °C, the Mo4/3B2–X-Zn anode maintains stable cycling for over 2800 h with a low overpotential of 58 mV at 0.5 mA cm–2. Pairing with the KVO cathode, the full cell delivers a capacity of up to 291.2 mA h g–1 at 0 °C and the pouch cell achieves 256.9 mA h g–1 under a high mass loading of 9.5 mg cm–2, demonstrating promising commercial potential.