Achieving stable Zn metal anode via a simple NiCo layered double hydroxides artificial coating for high performance aqueous Zn-ion batteries

Abstract

Aqueous Zn-ion batteries have become one of the most promising candidates for next-generation energy storage devices due to low price, nontoxicity, safety, and high theoretical capacity. However, the issues of Zn dendrite, H2 evolution, and corrosion severely hinder their future development. Here, a simple NiCo layered double hydroxides (NiCo-LDH) artificial coating is constructed on Zn anode (denoted as NCLZn) by spin-coating method. The prepared NiCo-LDH coating with abundant metal sites not only can increase the active sites to guide the uniform deposition of Zn2+, but also can suppress the side reactions as a physical barrier. Meantime, the NiCo-LDH coating also improves the wettability of electrolyte and reduces the interface resistance. Consequently, compared with bare Zn, the symmetric cells with NCLZn anode exhibit a stable overpotential (<20 mV) and long-time lifespan (2500 h) with remarkable coulombic efficiency (greater than99.0%) at 1 mA cm−2 and 1 mAh cm−2. A stable plating/stripping still can be achieved for more than 1580 h, even at 10 mA cm−2. Simultaneously, the NCLZn/MnO2 cells present impressive specific capacity of 153 mAh g−1 at 1 A g−1 after 1600 cycles. Therefore, this simple and low-cost method provides a positive strategy for the industrialization of aqueous Zn-ion batteries.