Hydrated WO3.0.33H2O nanorod for an excellent anode materials enables high performance and long-cycle stability for aqueous Zn-ion batteries

Metal dissolution and solid electrolyte interface layer growth are the most challenging issues in a reversible aqueous Zn-ion battery. To address this issue, an electrolyte-material marriage must be devise. Herein, we have develop the unique hydrate WO3.0.33H2O nanorods that integrate the layers and hexagonal tunnel structures for an aqueous Zn-ion battery. However, the one-dimensional morphology and confinement of the hydrate molecules of WO3.0.33H2O nanorods enable the superhighway and sub-second electron transport. Owing to this unique property, WO3.0.33H2O nanorods exhibit a capacity of 91 mAh g−1, which is two-fold higher than the three-dimensional WO3 cube in 1 M ZnCl2 electrolyte. Additionally, WO3.0.33H2O nanorods exhibit excellent durability and coulombic efficiency of 94 % and 99 % after 3000 cycles, respectively. To further examine the electrolyte suitability, the WO3.0.33H2O nanorods show excellent reversibility of the insertion and deinsertion of the Zn2+ ion in 1 m ZnCl2 compares to 1 M ZnSO4 and 1 M Zn(CH3COO)2 electrolytes. Therefore, this unique construction of hydrates WO3.0.33H2O nanorods would be a new avenue for designing the anode materials for a reversible aqueous Zn-ion battery.