Controllable and large‐area growth of ZnO nanosheet arrays under ambient condition as superior anodes for scalable aqueous batteries

Two‐dimensional (2D) oxides have been the focus of substantial research interest recently, owing to their fascinating physico‐chemical properties. However, fabrication of large‐area 2D oxide materials in a controlled manner under mild conditions still remains a formidable challenge. Herein, we develop a facile and universal strategy based on the sonochemistry approach for controllable and large‐area growth of quasi‐aligned single‐crystalline ZnO nanosheets on a Zn substrate (Zn@SC‐ZnO) under ambient conditions. The obtained ZnO nanosheets possess the desired exclusively exposed (00 1 ¯ $\mathop{1}\limits^{̅}$) facets, which have been confirmed to play a critical role in significantly reducing the activation energy and facilitating the stripping/plating processes of Zn. Accordingly, the constructed Zn@SC‐ZnO||Zn@SC‐ZnO symmetric cell has very low polarization overpotential down to ~20 mV, with limited dendrite growth and side reactions for Zn anodes. The developed Zn@SC‐ZnO//MnO2 aqueous Zn‐ion batteries (ZIBs) show a voltage efficiency of 88.2% under 500 mA g−1 at the stage of 50% depth of discharge, which is state of the art for ZIBs reported to date. Furthermore, the as‐assembled large‐size cell (5 cm × 5 cm) delivers an open circuit potential of 1.648 V, and can be robustly operated under a high current of 20 mA, showing excellent potential for future scalable applications. We report a controllable and large‐area growth strategy based on sonochemistry for the fabrication of single‐crystalline ZnO nanosheets under ambient conditions as a superb Zn anode with a very low polarization overpotential down to ~20 mV. The developed Zn@SC‐ZnO//MnO2 aqueous Zn‐ion batteries delivers a voltage efficiency of 88.2% under a current density of 500 mA g−1 at the stage of 50% depth of discharge.