An aqueous electrolyte densified by perovskite SrTiO₃ enabling high-voltage zinc-ion batteries

The conventional weak acidic electrolyte for aqueous zinc-ion batteries breeds many challenges, such as undesirable side reactions, and inhomogeneous zinc dendrite growth, leading to low Coulombic efficiency, low specific capacity, and poor cycle stability. Here, an aqueous densified electrolyte, namely, a conventional aqueous electrolyte with addition of perovskite SrTiO₃ powder, is developed to achieve high-performance aqueous zinc-ion batteries. The densified electrolyte demonstrates unique properties of reducing water molecule activity, improving Zn²⁺ transference number, and inducing homogeneous and preferential deposition of Zn (002). As a result, the densified electrolyte exhibits an ultra-long cycle stability over 1000 cycles in Zn/Ti half cells. In addition, the densified electrolyte enables Zn/MnO₂ cells with a high specific capacity of 328.2 mAh g^-1 at 1 A g^-1 after 500 cycles under an extended voltage range. This work provides a simple strategy to induce dendrite-free deposition characteristics and high performance in high-voltage aqueous zinc-ion batteries.