Ion-directed polymer/inorganic interphase with enriched charge for the stable and high-rate Zn anode

Abstract

The rate performance of the Zn anode is a crucial factor for the practical zinc-ion batteries, while concentration gradient and aggregation of zinc ions at the interface hinder its reversibility. Herein, we proposed an artificial solid electrolyte interphase on Zn foil by in-situ chemical corrosion, composed of external conducting polymer (PEDOT-SO3H) and internal layered zinc sulfate hydroxide hydrate (LZSH). The polymer layer provided the capacitive effect and ionic selectivity for Zn2+ enrichment, as well as repulsion for SO42- by negative charge. Spontaneously, the -SO3- group accelerated the desolvation of Zn(H2O)62+, thereby achieving fast plating kinetics. Moreover, by chemical corrosion and polymer restriction, the preferred orientation of LZSH along (001) was tailored, guiding the uniform deposition of zinc ions along (002) by lattice-lattice match. Consequently, the modulated anode (PZn) delivered an excellent rate performance at 20 mA cm-2 over 1500 h (cumulative plating capacity of 15 Ah cm-2). The full cell with KxMnO2 cathode delivered an impressive capacity retention of 80.1% at 1 A g-1 over 1000 cycles. The Ah-level pouch cell further demonstrated the practicality of aqueous zinc-ion batteries. This work offers a feasible strategy to tailor the functional interface by conducting polymer towards the practical Zn anode.