Bimetal-Initiated Concerted Zn Regulation Enabling Highly Stable Aqueous Zn-Ion Batteries

Abstract

Aqueous zinc ion batteries are highly sought after for the next generation of sustainable energy storage systems. However, their development is significantly impeded by the presence of undesired zinc dendrites, which greatly reduce their cycle life. It is well-received that surface passivation by introducing foreign metals represents a compelling measure to enhance the stability of Zn anodes. Nevertheless, the vast potential of effecting concerted interplay between multiple metal elements for enhanced overall performance in Zn ion batteries remains elusive, due to the overwhelming challenge in creating uniform textures from hetero-units and understanding the mechanism underlying the synergistic performance gain. In this work, an innovative bimetallic overlaying strategy is proposed that renders possible the synergy between AgZn3 and CuZn5 in effecting uniform Zn deposition in a laterally confined and compact manner. The seeded growth of Zn on the bimetal-modulated interface effectively reduces the nucleation potential barrier, yielding a low nucleation overpotential (25 mV). In full cell testing with a commercial MnO2 applied as the cathode, superb cycling stability, surpassing the results reported in previous works, is achieved. The cell delivers an outstanding remaining capacity of 215 mA h g−1 after 300 cycles with almost no capacity degradation observed. The simple and highly efficient bimetal design, which synergizes the strengths of distinct metals, has the potential to drive innovations in the development of multicomponent aqueous Zn batteries with exceptional performance.