Synergistic electrostatic shielding manipulation of Na+ and desolvation effect of Zn2+ enabled by glycerol for long-lifespan and dendrite-free Zn anodes

The development of aqueous Zn-based energy storage devices is severely restricted by uncontrollable Zn dendrite growth, serious parasitic side-reactions, and poor low-temperature performance. In this work, we introduce glycerol (Gl) with an appropriate concentration of 2.1 M (mol L-1) as a synergistic manipulator and desolvater in the 1 M Zn(ClO4)2 and 0.5 M Na2SO4 electrolyte for zinc batteries. Theoretical calculations and experimental analysis confirm that the Gl-Na+ structure adsorbs onto the Zn anode during the plating process, which increases the electrostatic shielding area of negative charge on Zn dendrites and thus inhibit their growth. Meanwhile, the desolvation effect of Zn2+ enabled by Gl promotes the optimization of solvated structure, resulting in uniform deposition of Zn2+. Additionally, Gl suppresses parasitic side-reactions and coagulation of the electrolyte to ensure a homogeneous electrode surface and improve low-temperature performance. In the modified electrolyte, stable Zn plating-stripping has been achieved for 2930 h at 2 mA cm-2 and 1 mA h cm-2, which is about 7.5 times longer than that in the Gl-free electrolyte. Moreover, even at-10 celcius, the hybrid capacitor with activated carbon and V2O5//Zn full battery realizes 95.37% and 62.84% capacity retention after 30,000 and 3000 cycles, respectively. This work presents an effective strategy for the synergism of double additives to promote the stability of the Zn electrode for high-performance aqueous batteries.