摘要

The low energy efficiency and limited cycling life of rechargeable Zn-air batteries (ZABs) arising from the sluggish oxygen reduction/evolution reactions (ORR/OERs) severely hinder their commercial deployment. Herein, a zeolitic imidazolate framework (ZIF)-derived strategy associated with subsequent thermal fixing treatment is proposed to fabricate dual-atom CoFeNC nanorods (Co1Fe1NC NRs) containing atomically dispersed bimetallic Co/Fe sites, which can promote the energy efficiency and cyclability of ZABs simultaneously by introducing the low-potential oxidation redox reactions. Compared to the mono-metallic nanorods, Co1Fe1NC NRs exhibit remarkable ORR performance including a positive half-wave potential of 0.933 V versus reversible hydrogen electrode (RHE) in alkaline electrolyte. Surprisingly, after introducing the potassium iodide (KI) additive, the oxidation overpotential of Co1Fe1NC NRs to reach 10 mA cm-2 can be significantly reduced by 395 mV compared to the conventional destructive OER. Theoretical calculations show that the markedly decreased overpotential of iodide oxidation can be ascribed to the synergistic effects of neighboring CoFe diatomic sites as the unique adsorption sites. Overall, aqueous ZABs assembled with Co1Fe1NC NRs and KI as the air-cathode catalyst and electrolyte additive, respectively, can deliver a low charging voltage of 1.76 V and ultralong cycling stability of over 230 h with a high energy efficiency of approximate to 68%. @@@ A zeolitic imidazolate framework (ZIF)derived strategy associated with subsequent thermal fixing treatment is proposed to fabricate dual-atom CoFeNC nanorods containing atomically dispersed bimetallic Co/Fe sites, which can be used as bifunctional air-cathode catalysts to boost the energy efficiency and cyclability of Zn-air batteries simultaneously by introducing low-potential oxidation redox reactions.image

  • 单位
    清华大学

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