Modulating Cation Migration and Deposition with Xylitol Additive and Oriented Reconstruction of Hydrogen Bonds for Stable Zinc Anodes

Highly reversible plating/stripping in aqueous electrolytes is one of the critical processes determining the performance of Zn-ion batteries, but it is severely impeded by the parasitic side reaction and dendrite growth. Herein, a novel electrolyte engineering strategy is first proposed based on the usage of 100 mM xylitol additive, which inhibits hydrogen evolution reaction and accelerates cations migration by expelling active H2O molecules and weakening electrostatic interaction through oriented reconstruction of hydrogen bonds. Concomitantly, xylitol molecules are preferentially adsorbed by Zn surface, which provides a shielding buffer layer to retard the sedimentation and suppress the planar diffusion of Zn2+ ions. Zn2+ transference number and cycling lifespan of Zn parallel to Zn cells have been significantly elevated, overwhelmingly larger than bare ZnSO4. The cell coupled with a NaV3O8 cathode still behaves much better than the additive-free device in terms of capacity retention.

Automated summary

By using a 100 mM xylitol additive, the plating/stripping processes in Zn-ion batteries can achieve high reversibility. The xylitol molecules not only inhibit the hydrogen evolution reaction, but also accelerate the migration of cations through the expelling of active H2O molecules and weakening of electrostatic interactions. Additionally, the preferential adsorption of xylitol molecules on the Zn surface forms a shielding buffer layer, which hinders the sedimentation and diffusion of Zn2+ ions.