科研之友
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摘要
Fast-charging technology plays a pivotal role in propelling the commercialization of zinc-air batteries (ZABs). While the lifetime of ZABs under fast-charging is severely shortened by the abundant O2 bubbles and the deactivation of the cathode catalysts. Herein, a defective MoCo/NC electrocatalyst is presented with Co nanoparticles and molybdenum-oxo subnano clusters by pyrolyzing the Lindqvist polyoxometalate incorporated ZIF-67 precursor. The crystalline defects are exacerbated by doping the polyoxometalate into the pores of ZIF-67. Furthermore, the accessibility of the pore defects is increased by Mo-leaching during the pre-activation. These accessible pore defects effectively prevent the exfoliation of catalysts from the support under the attack of O2 bubbles, and improve the electrolyte penetration. Besides, the pore defects offer numerous active sites for the electrocatalytic reactions, resulting in an active and stable MoCo/NC catalyst. Hence, such a MoCo/NC electrocatalyst achieves a long lifetime of 1538 h at 5 mA cm-2, and a long lifetime of 641 h under a fast charge of 50 mA cm-2 in the homemade ZAB. The unique components and operational mechanisms propel scientists to portray splendid blueprints for durable fast-charging ZABs for potential industrial applications. The MoCo/NC bifunctional oxygen electrocatalyst with accessible pore defects is constructed by the ' dopant-leaching ' strategy. The Mo-leaching induced accessible pore defects are conducive to the electrolyte penetration and the transfer of O2 bubbles. Besides, the pore defects offer numerous active sites for the electrocatalytic reactions, resulting in highly tolerant and active cathode electrocatalysts for fast-charging ZABs. image
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