Electronic Structure Tunable Metallosupramolecular Polymers as Bifunctional Electrocatalysts for Rechargeable Zn-Air...

Metallosupramolecular polymers (MSPs) have shown great potential in the area of oxygen electrocatalysis due to their tunable electronic structure, and predictable coordination environment. Further exploration of structure-performance relationships of oxygen electrocatalysts is crucial for designing highly efficient catalysts. Herein, a strategy is proposed to prepare MSP-based bifunctional oxygen electrocatalysts with different oxygen electrocatalytic preferences (Co-AQ and Co-AN) by adjusting the electronic structure of organic linkers. The electronic effects of organic linkers significantly influence the adsorbate evolution mechanism. Co-AQ, with an electron-withdrawing linker, demonstrated superior OER activity among the two with an overpotential of 280 mV at 10 mA cm^-2 and 340 mV at 50 mA cm^-2. In contrast, Co-AN, with an electron-donating linker, exhibited outstanding ORR activity with a large limiting current density of 6.14 mA cm^-2. Furthermore, the Co-AQ-based Zn-air battery showed a high power density (135 mW cm^-2) and excellent cycling stability of 100 h. This work presents a novel approach for adjusting bifunctional oxygen electrocatalysis performance and further reveals the structure-performance relationships of oxygen electrocatalysts.