Mn-Doped Zn Metal–Organic Framework-Derived Porous N-Doped Carbon Composite as a High-Performance Nonprecious Electrocatalyst for Oxygen Reduction and Aqueous/Flexible Zinc–Air Batteries

Abstract

Developing low-cost, efficient, and stable oxygen reduction reaction (ORR) electrocatalysts is crucial for the commercialization of energy conversion devices such as metal–air batteries. In this study, we report a Mn-doped Zn metal–organic framework-derived porous N-doped carbon composite (30-ZnMn-NC) as a high-performance ORR catalyst. 30-ZnMn-NC exhibits excellent electrocatalytic activity, demonstrating a kinetic current density of 9.58 mA cm–2 (0.8 V) and a half-wave potential of 0.83 V, surpassing the benchmark Pt/C and most of the recently reported non-noble metal-based catalysts. Moreover, the assembled zinc–air battery with 30-ZnMn-NC demonstrates high peak power densities of 207 and 66.3 mW cm–2 in liquid and flexible batteries, respectively, highlighting its potential for practical applications. The excellent electrocatalytic activity of 30-ZnMn-NC is attributed to its unique porous structure, the strong electronic interaction between metal Zn/Mn and adjacent N-doped carbon, as well as the bimetallic Mn/Zn–N active sites, which synergistically promote faster reaction kinetics. This work offers a controllable design strategy for efficient electrocatalysts with porous structures and bimetallic active sites, which can significantly enhance the performance of energy conversion devices.

Origin of the Oxygen Reduction Activity on Boron-Doped Fe–N–C Catalysts for Zinc–Air Battery Applications

“…The real-time application of these materials was analyzed using the solid-state ZAB (Figure a), wherein catalyst-coated carbon paper and zinc foil were used as the electrode materials, respectively. The KOH-containing PVA gel was synthesized as reported previously (see Supporting Information) and used as the gel electrolyte. The solid-state ZAB assembly shows the highest OCP (1.5 V), and the polarization plot shows a power density of 39 mW cm –2 at a current density of 60 mA cm –2 (Figure b).…”

Active site exploration of core–corona structured bifunctional cobalt ferrite-containing nitrogen-doped carbon nanotubes for rechargeable zinc–air battery application

“…The solid-state zinc–air battery experiment was performed using the gel electrolyte prepared from polyvinyl alcohol (PVA) and KOH, 49 as shown in Fig. 6c and d.…”

Design Principles and Mechanistic Understandings of Non-Noble-Metal Bifunctional Electrocatalysts for Zinc–Air Batteries

“…Metal–organic frameworks (MOFs) with porous structure, high surface area and increased number of active sites, have attracted great interest of researchers [ 90 ]. Wang et al designed porous cake-like ZnMn–NC by loading Mn into Zn–MOF and pyrolysis, resulting in an enhanced ORR activity [ 91 ]. The 3D electrocatalysts with many exposed active sites accelerated the activation of reactants/intermediates, and the irregular morphological features optimized the triple-phase interface [ 92 , 93 ].…”