AgI Nanoplates in Unusual 7H/9R Structures: Highly Ionically Conducting Polytype Heterostructures

Abstract

Homogeneous AgI nanoplates in diameter and in thickness can be prepared by a solution-based route using poly(diallyldimethylammonium chloride) as capping agent. The formation of unusual 7H/9R polytype modifications is the origin of the huge room temperature superionic conductivity and the large hysteresis in the phase transition with respect to the superionic high-temperature phase . All these properties indicate a substantial Ag disorder in the 7H/9R polytype AgI unlike the normal in wurtzite structure. The Ag disorder in 7H/9R polytype structure can be formally understood in terms of an equilibrium redistribution of charge carriers at heterojunctions in ionically conducting zinc blende heterostructures in the subnano regime. Upon martensitic transformation of with its body-centered-cubic iodine lattice, the 7H/9R stacking sequence rather than the 2H sequence of occurs in the presence of attracting surface adsorbents of . The usability of these materials as electrolytes in rechargeable all-solid-state Ag batteries working at was demonstrated by using Ag as anode and as cathode.