KR-102963164-B1 - MACHINE LEARNING ACCELERATED IDENTIFICATION OF BIFUNCTIONAL ACTIVE SITES IN METAL-ORGANIC FRAMEWORK DERIVED METAL OXIDE HETEROSTRUCTURES FOR HIGH-PERFORMANCE METAL-AIR BATTERIES
Abstract
The present invention relates to an air electrode for a metal-air battery comprising a cobalt-manganese heterojunction structure, a metal-air battery comprising the same, and a method for manufacturing a cobalt-manganese heterojunction structure. The cobalt-manganese heterojunction structure according to the embodiments of the present invention exhibits excellent oxygen reduction reaction activity and durability, and can exhibit excellent OER performance including a high current density that surpasses RuO2 oxygen evolution reaction catalysts.
Inventors
- 강정구
- 최종휘
- 김동원
- 아디얏마, 압둘아만
Assignees
- 한국과학기술원
Dates
- Publication Date
- 20260511
- Application Date
- 20240229
- Priority Date
- 20231027
Claims (19)
- An air electrode for a zinc-air battery comprising a cobalt-manganese heterojunction structure including cobalt oxide and manganese oxide, The above cobalt-manganese heterojunction structure is manufactured by a method of mixing a cobalt precursor, a manganese precursor, and a solvent and performing a solvent thermal reaction to obtain a cobalt-manganese layered double hydroxide, and heat-treating the cobalt-manganese layered double hydroxide to obtain a cobalt-manganese heterojunction structure. The above cobalt oxide contains CoO, and the above manganese oxide contains Mn₃O₄ , and The interface between the above cobalt oxide and the above manganese oxide contains oxygen defects, and The particle size of the above cobalt-manganese heterojunction structure is 10 nm to 500 nm, and The above cobalt-manganese heterojunction structure is an air electrode having dual functional catalytic activity for oxygen evolution and oxygen reduction reactions.
- In Article 1, The above cobalt-manganese heterojunction structure is a flower-like air electrode.
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- In Article 1, An air electrode having a current density value of 500 mA cm⁻² or more of the above cobalt-manganese heterojunction structure.
- In Article 1, The above cobalt-manganese heterojunction structure is an air electrode having an overpotential value of 300 mV or less at a current density of 10 mA cm⁻² .
- In Article 1, The above cobalt-manganese heterojunction structure is an air electrode in which a lattice oxygen oxidation mechanism is activated due to the oxygen defect.
- In Article 1, Air electrode including additional materials.
- A zinc-air battery comprising an air electrode according to claim 1; an anode containing zinc; and an electrolyte.
- In Article 11, The above zinc-air battery is a zinc-air battery having an energy density value of 875 Wh kg⁻¹ or more at a discharge current rate of 10 mA cm⁻² .
- In Article 11, The above zinc-air battery is a zinc-air battery having a metal utilization rate of 97% or higher.
- In Article 11, A zinc-air battery having a cycle life of 600 cycles or more.
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Description
Machine Learning Accelerated Identification of Bifunctional Active Sites in Metal-Organic Framework-Derived Metal Oxide Heterostructures for High-Performance Metal-Air Batteries The present invention relates to an air electrode for a metal-air battery comprising a cobalt-manganese heterojunction structure, a metal-air battery comprising the same, and a method for manufacturing a cobalt-manganese heterojunction structure. Over the past few decades, the demand and market size for electrochemical energy storage (ESS) systems have surged across a wide range of applications, from portable devices to electric vehicles and large-scale grid systems. However, due to safety issues and energy density limitations of currently commercialized lithium-ion batteries (LIBs), there is a demand for more advanced ESSs with higher energy densities. Zinc-air batteries (Zn-air batteries; ZABs) are attracting attention as a solution to these problems due to their theoretically high energy density, low cost, eco-friendliness, and significantly lower fire risk. In this system, atmospheric oxygen is utilized at the air cathode; during discharge, oxygen is reduced to hydroxide via the oxygen reduction reaction (ORR), and during charging, the hydroxide is oxidized to release oxygen via the oxygen evolution reaction (OER). Because oxygen is drawn directly from the air, ZABs can, in principle, achieve higher gravimetric and volumetric energy densities than commercial LIBs. However, the slow kinetics of the four-electron transfer step and slow oxygen mass transport associated with ORR and OER remain major challenges in realizing high power density and charge-discharge cycle stability, consequently preventing ZAB from fully utilizing its theoretically high energy density. Noble metal-based catalysts (e.g., RuO2 for OER and Pt/C for ORR) have been shown to exhibit excellent catalytic activity for ORR and OER. However, combining different catalysts on the same cathode is very difficult. Furthermore, the high cost and scarcity of novel metals limit their use in practical applications. FIG . 1 illustrates, in one embodiment of the present invention, a synthesis procedure for a dual-functional CoO- Mn₃O₄ heterostructure (CMH), a global optimization strategy combined with a machine learning force field for identifying the CMH structure, and a schematic description of the oxygen reduction reaction and oxygen evolution reaction mechanisms in a CMH-based zinc-air battery. FIGS. 2a to 2l represent the measurement of morphological characteristics of ZIF-67, CoMn LDH, and CMH in one embodiment of the present invention, showing low-magnification and high-magnification SEM images of dodecahedral Mn-doped ZIF-67 (a, b), flower-shaped CoMn LDH (c, d), and CMH (e, f); a TEM image of CMH (g); an HRTEM image of CMH, the corresponding FFT pattern, and an HRTEM image of CMH (h); and a STEM elemental mapping image of CMH (il). FIGS. 3a to f show the powder XRD patterns of Co/Mn LDH (a) and CMH (b); the survey XPS spectrum (c); and the high-resolution XPS spectra of O 1s (d), Mn 2p (e), and Co 2p (f), as measured for the characteristics of CMH materials in one embodiment of the present invention. FIGS. 4a to 4f represent the results of electrochemical characterization of electrocatalytic activity in one embodiment of the present invention, showing ORR polarization curves measured using RDE of various rotational speeds (a); KL p-plots at voltages of 0.3 V to 0.55 V (vs. RHE) derived from RDE measurement results (inset: number of electron transfers in the ORR process by CMH) (b); ORR polarization curves of CoO, Co3O4 , and CMH (c); OER polarization curves of CoO, Co3O4 , RuO2 , and CMH (d); comparison of half-wave potential and overpotential for various samples (e); and oxygen reduction and generation polarization curves of CMH (f). FIGS. 5 a to g represent the results of a performance evaluation of a zinc-air battery (ZAB) in one embodiment of the present invention, showing an OCV plot (inset: OCV measured with a multimeter) (a); a photograph of an LED driven by two ZABs (b); a discharge polarization curve and the corresponding power density curve (c); a constant current charge/discharge cycling curve at a current density of 10 mA cm⁻² (d); a rate performance test at various current densities (e); the specific capacity and energy density of the zinc-air battery (f); and the ratio of the power density of a conventionally reported sample to a noble metal catalyst (g). FIG. 6 shows an SEM image (a) of a flower-shaped Co/Mn-LDH in one embodiment of the present invention; and corresponding element mapping images (b to f). FIG. 7 shows the ORR polarization curves of benchmarking Pt/c and CCM at a rotational speed of 1600 rpm in one embodiment of the present invention. FIG . 8 shows the ORR polarization curves of a metal oxide single phase (CoO and Mn₃O₄ ), a noble metal oxide ( RuO₂ ), and CMH in one embodiment of the present invention. FIG. 9 shows the OER polarizatio