One‐Dimensional Crystalline Zn2+ Conduction by Labile Tetrahedral Motifs

By integrating polarizable I⁻ and chelating ligands, a sequenced 1D Zn²⁺ conduction architecture is constructed in a crystalline complex. The labile Zn–I⁻ binding coupling with localized anionic disordering promote Zn²⁺ diffusion in a “pulley block” manner, breaking the Coulombic penalties inherent to multivalent-ion transport in solids. This work establishes a novel design paradigm for solid electrolytes that tolerate multivalent cations.

Abstract

Switching from liquid electrolytes to solid-state electrolytes (SSEs) overcome irreversible issues encountered in energy-dense electrodes through mechanically and ionically stable solid–solid redox reactions. Most advances are achieved by the discoveries on monovalent-cation conduction behaviors in SSEs, whereas practically feasible divalent-cation conduction is formidably challenging in solids, essentially due to the lack of tailored anionic frameworks tolerating charge-dense cations. Here, through a precise design of coordination geometry controlled by highly polarizable anionic ligands, a specialized single-crystal framework containing continuous Zn²⁺-conducting channels is engineered with mitigated Coulombic penalties. The ordered 1D architecture with tailored tetrahedral ZnI₄ ²⁻ integrating labile Zn²⁺-I⁻ interplays and anionic disordering dynamics induces enhanced Zn²⁺ diffusion in a “pulley block” manner, achieving a conductivity of 6.44 × 10⁻⁵ S cm⁻¹ (at 30 °C) surpassing conventional Zn²⁺-conducting SSEs by three orders of magnitude. This work establishes a new paradigm for multivalent-cation conducting solid frameworks based on simultaneous anion modulation and coordination engineering, unlocking pathways toward energy-dense post-Li batteries.