The slow reaction kinetics of oxygen electrode is the bottleneck restricting the development of rechargeable Zn-air batteries (ZABs). In order to further improve the energy conversion efficiency of ZABs, a novel urea-assisted ZAB system was proposed by replacing oxygen evolution reaction (OER) with urea oxidation reaction (UOR) with lower theoretical thermodynamic potential. Inspired by nature’s ingenious structure-function, a “leaf-branch” CoNi@NCNTs-LDH/CC binary-site electrocatalyst was designed for the above system, where spatially separated branches and leaves serve as the main active sites for ORR and UOR, respectively. A build-in electric field from CoNi-LDH to CoNi@NCNTs is formed at the interface of the composite, which plays a command effect, effectively triggering the accumulation of O and urea reactants around the CoNi and LDH sites, respectively, and thus improving the efficiency of both ORR and UOR reactions. Based on that, a conceptual urea-assisted rechargeable ZAB is demonstrated to have significantly decreased charging voltage, higher energy conversion efficiency (74.6 %) compared with the conventional ZAB, as well as high urea elimination rates. Considering the urea-assisted ZAB with high energy conversion efficiency and wastewater treatment versatility as an energy transfer station applied in a high value-added agricultural system, uninterrupted hydrogen production and wastewater treatment of agricultural wastewater can be simultaneously achieved using sustainable energy sources.

中文翻译：

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用于新型尿素辅助锌空气电池的仿生二元催化剂：可再生能源和氢气之间的中转站


氧电极缓慢的反应动力学是制约可充电锌空气电池（ZABs）发展的瓶颈。为了进一步提高ZABs的能量转换效率，提出了一种新型尿素辅助ZAB系统，用理论热力学势较低的尿素氧化反应（UOR）代替析氧反应（OER）。受大自然巧妙结构功能的启发，针对上述系统设计了“叶-枝”CoNi@NCNTs-LDH/CC二元位点电催化剂，其中空间分离的枝和叶分别作为ORR和UOR的主要活性位点。复合材料界面处形成从CoNi-LDH到CoNi@NCNTs的内建电场，起到指挥作用，有效触发O和尿素反应物分别在CoNi和LDH位点周围聚集，从而改善ORR 和 UOR 反应的效率。基于此，与传统ZAB相比，概念性尿素辅助可充电ZAB被证明具有显着降低的充电电压、更高的能量转换效率（74.6％）以及高尿素消除率。考虑到具有高能量转换效率和废水处理多功能性的尿素辅助ZAB作为应用于高附加值农业系统的能量中转站，可以使用可持续能源同时实现不间断的制氢和农业废水的废水处理。