Macromolecular electrolyte engineering for tuning Zn-ion solvation chemistry and boosting H+ storage toward stable aqueous zinc-organic batteries†

Abstract

Aqueous zinc-organic batteries (AZOBs) have attracted attention because they have the advantages of both organic batteries and aqueous zinc-ion batteries. Nevertheless, the hydrogen evolution reaction and the unrestrained growth of Zn dendrites still limit the further development of AZOBs. In this work, we demonstrate that the macromolecular electrolyte engineering using porphyrin derivatives with different peripheral substituents could not only restrain the solvation sheath of Zn²⁺ and inhibit the parasitic reactions but also boost H⁺ storage for AZOBs. Among various porphyrin derivatives, the tetraphenylporphyrin tetrasulfonic acid (TPPS) additive has the ability to facilitate the formation of a Zn-porphyrin complex to promote uniform Zn²⁺ deposition, resulting in superior Zn symmetric cells with longer cycling stability over 900 h and smaller overpotential of 35.3 mV. Furthermore, the full cell and pouch-type cell with quinone-fused aza-phenazine (QAP) cathode also exhibit impressive electrochemical performance. Even at different bending angles, the change in specific capacities of pouch-type cells is negligible. These findings furnish an advanced concept for the application of porphyrin derivatives as an additive for the further development of AZOBs.