TAC-linked multimetal MOF enables 13-day cycling in rechargeable zinc–air battery

A multimetal metal–organic framework film linked with trimesic acid delivered the best performance among the zinc–air battery electrodes tested in an experimental study. The material achieved a current density of 60 mA cm−2 and remained stable for more than 13 days during long-term cycling at 5 mA cm−2. The framework combined nickel, cobalt, iron and manganese centers and was evaluated as a bifunctional air electrode for rechargeable zinc–air batteries, where it was designed to support both oxygen reduction and oxygen evolution.

Silvia N. Cruz Orellana, Próspero Acevedo-Peña and Edilso Reguera synthesized the polymetallic framework films directly on carbon cloth through cathodic electrodeposition. The investigators varied the organic ligand while retaining the same four metal centers, allowing them to examine how carboxylate coordination affected the resulting electrocatalysts. Three ligands were compared: terephthalic acid, abbreviated BDC; 2,6-naphthalenedicarboxylic acid, abbreviated NDC; and trimesic acid, abbreviated TAC. The study focused on the relationship between ligand structure, catalytic behavior and performance in assembled rechargeable zinc–air batteries.

Electrochemical characterization showed that the oxygen-evolution behavior differed clearly among the three frameworks. The NDC-based metal–organic framework required the lowest oxygen-evolution overpotential, 310 mV at 10 mA cm−2. The TAC- and BDC-based materials followed with overpotentials of 340 and 350 mV, respectively, at the same current density. The researchers associated this ordering with electrochemically active surface area. Their analysis further suggested that ligand modification redistributed electrons at the metal sites and strengthened metal–oxygen interactions, particularly in the NDC- and TAC-based materials. These interpretations link coordination and surface properties to catalytic performance, but the reported findings do not provide a complete account of the reaction mechanism or the structure of the active material throughout operation.

Measurements of oxygen reduction were more similar across the framework series. All three samples had half-wave potentials of approximately 0.76 V. Koutecky–Levich analysis nevertheless gave the TAC-based material an estimated electron-transfer number of about 3.8, indicating a greater contribution from the four-electron pathway than in the other samples. The similar half-wave potentials mean that this difference did not create a large separation in that particular oxygen-reduction metric. By contrast, the strongest overall results appeared when the films were incorporated into complete rechargeable zinc–air batteries and tested under device operating conditions.

The TAC-based multimetal framework delivered the strongest battery performance reported in the study. Assembled devices operated at a current density of 60 mA cm−2, showed a charge–discharge voltage gap of approximately 0.8–0.9 V and achieved a round-trip efficiency of about 60%. Long-term cycling at 5 mA cm−2 demonstrated stable operation for more than 13 days. The results indicate that selecting the carboxylate linker can influence both the measured catalytic properties of a multimetal metal–organic framework and its behavior in a rechargeable zinc–air battery configuration. The finding remains an experimental demonstration of the specific electrodes and operating conditions tested; the supplied study summary does not establish performance against commercial benchmarks or identify the long-term degradation mechanisms responsible for battery durability.

Subject of Research: Ligand-controlled multimetal metal–organic framework electrocatalysts for rechargeable zinc–air batteries

Article Title: Carboxylate coordination effects on multimetal MOFs as bifunctional electrocatalysts for Zn–air batteries

Article References: Orellana, S. N. C., Acevedo-Peña, P., & Reguera, E. (2026). Carboxylate coordination effects on multimetal MOFs as bifunctional electrocatalysts for Zn–air batteries. Journal of Materials Science, 61(40), 30665-30682. https://doi.org/10.1007/s10853-026-13662-3

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13662-3

Keywords: zinc–air batteries, metal–organic frameworks, bifunctional electrocatalysts, oxygen reduction, oxygen evolution, trimesic acid, carboxylate ligands, electrodeposition, multimetallic materials, battery cycling, Carboxylate, coordination