Understanding the active site in chameleon-like bifunctional catalyst for practical rechargeable zinc-air batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39511234.
- Also identified by DOI 10.1038/s41467-024-54019-1 and PMC identifier 11544253.
- Licence recorded as CC BY-NC-ND.
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Abstract
The practical application of rechargeable zinc-air batteries faces challenges stemming from inadequate bifunctional catalysts, contradictory gas-liquid-solid three-phase interfaces, and an ambiguous fundamental understanding. Herein, we propose a chameleon-like bifunctional catalyst comprising ruthenium single-atoms grafted onto nickel-iron layer double hydroxide (Ru<sub>SA</sub>-NiFe LDH). The adaptive oxidation of Ru<sub>SA</sub>-NiFe LDH to oxyhydroxide species (Ru<sub>SA</sub>-NiFeOOH) during charging exposes active sites for the oxygen evolution reaction, while reversible reduction to NiFe LDH during discharge exposes active sites for the oxygen reduction reaction. Additionally, a hierarchical air cathode featuring hydrophilic and hydrophobic layers facilitates the reversible conversion between Ru<sub>SA</sub>-NiFe LDH and Ru<sub>SA</sub>-NiFeOOH, expedites oxygen bubble desorption, and suppresses carbon corrosion. Consequently, our zinc-air batteries demonstrate a high charge/discharge capacity of 100 mAh cm<sup>-2</sup> per cycle, a voltage gap of 0.67 V, and an extended cycle life of 2400 h at 10 mA cm<sup>-2</sup>. We comprehensively elucidate the catalytic reaction thermodynamics and kinetics for the air cathode through electrode potential decoupling monitoring, oxygen bubble desorption tracking, and carbon content quantification.