Kumar Sanath, Fu Yen-Pei
Department of Materials Science and Engineering, National Dong Hwa University, Shou-Feng, Hualien 974301, Taiwan.
Department of Materials Science and Engineering, National Dong Hwa University, Shou-Feng, Hualien 974301, Taiwan.
J Colloid Interface Sci. 2025 Jul 2;700(Pt 1):138328. doi: 10.1016/j.jcis.2025.138328.
This work focuses on the preparation of nanostructured MnO by reducing a zeolite imidazole framework and integrating it with hydrothermally synthesized nickel aluminum-layered double hydroxide (NiAl-LDH) nanosheets. Morphological analysis reveals that the electrocatalysts exhibit nanostructures, with the oxide showing a spherule-like morphology and the LDH presenting a sheet-like morphology. Additionally, high-resolution transmission electron microscopy has been used to study their structure. Electrochemical studies conducted in an alkaline medium reveal that the MnO@NiAl-LDH exhibits a bi-functional capability for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), with a potential difference of 0.72 V between OER and ORR. Furthermore, the nanostructured MnO@NiAl-LDH exhibited excellent stability, with a relative current of 98 % for OER and 79 % for ORR over a period of 24 h and 12 h, respectively. To support the obtained electrochemical performance, in-situ Raman analysis is carried out to explain the electron transfer mechanism in detail. Furthermore, the fabricated zinc-air battery (ZAB), with Mn₃O₄@NiAl-LDH as air cathode, undergoes various assessments, including specific capacity, multi-step current input, reversibility, and stability under different current densities. The ZAB demonstrated impressive endurance, lasting over 300 h at 2 mA/cm and 190 h at 5 mA/cm. To meet the requirements of wearable technology, the ZAB is made flexible by employing a polymer gel electrolyte, resulting in a flexible ZAB. This flexible version achieved an excellent working potential of 1.34 V and a power density of 84 mW/cm, exhibiting stable performance for 24 h. Additionally, the flexible ZAB performance is analyzed in conjunction with other environmental conditions, including negative temperatures. Finally, a practical demonstration was conducted by connecting two ZABs in series, successfully powering an LED, and running miniature fans. These results highlight Mn₃O₄@NiAl-LDH as an efficient electrocatalyst for air cathode applications in ZABs.
这项工作重点在于通过还原沸石咪唑框架制备纳米结构的MnO，并将其与水热合成的镍铝层状双氢氧化物（NiAl-LDH）纳米片整合。形态分析表明，电催化剂呈现纳米结构，氧化物表现出球状形态，而LDH呈现片状形态。此外，高分辨率透射电子显微镜已用于研究它们的结构。在碱性介质中进行的电化学研究表明，MnO@NiAl-LDH对析氧反应（OER）和氧还原反应（ORR）具有双功能能力，OER和ORR之间的电位差为0.72 V。此外，纳米结构的MnO@NiAl-LDH表现出优异的稳定性，在24小时和12小时内，OER的相对电流分别为98%，ORR的相对电流为79%。为了支持所获得的电化学性能，进行原位拉曼分析以详细解释电子转移机制。此外，以Mn₃O₄@NiAl-LDH作为空气阴极制造的锌空气电池（ZAB）进行了各种评估，包括比容量、多步电流输入、可逆性以及在不同电流密度下的稳定性。该ZAB表现出令人印象深刻的耐久性，在2 mA/cm下持续超过300小时，在5 mA/cm下持续190小时。为满足可穿戴技术的要求，通过采用聚合物凝胶电解质使ZAB变得灵活，从而得到柔性ZAB。这种柔性版本实现了1.34 V的优异工作电位和84 mW/cm的功率密度，在24小时内表现出稳定的性能。此外，结合包括负温度在内的其他环境条件对柔性ZAB的性能进行了分析。最后，通过将两个ZAB串联进行了实际演示，成功为一个LED供电并驱动微型风扇。这些结果突出了Mn₃O₄@NiAl-LDH作为ZAB空气阴极应用的高效电催化剂。
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