Computational discovery of cathode materials for rechargeable aqueous zinc-ion batteries

TL;DR

This study computationally screened over 2000 materials to identify promising cathodes for aqueous zinc-ion batteries, aiming to improve stability and performance for grid-scale energy storage.

Contribution

It introduces a comprehensive computational approach to discover new stable cathode materials for RAZIBs, highlighting 10 promising candidates for experimental validation.

Findings

Identified 10 new cathode materials with high potential for RAZIBs.

Established the role of transition metal oxidation states in intercalation potential.

Provided insights into structural and chemical factors affecting stability and capacity.

Abstract

Rechargeable aqueous zinc-ion batteries (RAZIBs) attract considerable scientific and commercial interest for deployment in grid-scale energy storage due to higher safety and lower manufacturing cost when compared to lithium-ion batteries. However, currently studied cathode materials suffer from severe capacity fade when cycling at rates appropriate for grid-scale applications ($<$ C/2), which hampers the commercialization of RAZIBs. To address the present limitation on cathode material availability, more than 2000 previously synthesized oxides, chalcogenides, Prussian blue analogues, and polyanion materials were computationally screened for the discovery of highly stable RAZIB cathode materials. The structural, electrochemical, and chemical properties of the materials were respectively evaluated through an investigation of the available Zn$^{2+}$ percolation paths in the crystal structure, the stability of the material in aqueous media under RAZIB operation conditions, and the attained transition metal oxidation state during cycling. The transition metal oxidation state and intercalating ion coordination environment were determined to govern the magnitude of the calculated intercalation potential, with this finding directly supporting the development of batteries with high operation potentials. Finally, 10 previously unexplored materials were identified with leading metrics for operation as RAZIB cathode materials, such as high Zn$^{2+}$ (de)intercalation potential, electrochemical stability, theoretical gravimetric capacity, and energy density, being here proposed for experimental testing. The materials identified in this study demonstrate a guide for advancing the available cathode materials for RAZIB, and help expedite the establishment of RAZIB as a commercially viable technology for grid-scale energy storage.