Amorphous MnO 2 Lamellae Encapsulated Covalent Triazine Polymer-Derived Multi-Heteroatoms-Doped Carbon for ORR/OER Bifunctional Electrocatalysis.

The intelligent construction of non-noble metal materials that exhibit reversible oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with bifunctional electrocatalytic performance is greatly coveted in the realm of zinc-air batteries (ZABs). Herein, a crafted structure-amorphous MnO ₂ lamellae encapsulated covalent triazine polymer-derived N, S, P co-doped carbon sphere (A-MnO ₂ /NSPC) is designed using a self-doped pyrolysis coupled with an in situ encapsulation strategy. The customized A-MnO ₂ /NSPC-2 demonstrates a superior bifunctional electrocatalytic performance, confirmed by a small ΔE index of 0.64 V for ORR/OER. Experimental investigations, along with density functional theory calculations validate that predesigned amorphous MnO ₂ surface defects and abundant heteroatom catalytic active sites collectively enhance the oxygen electrocatalytic performance. Impressively, the A-MnO ₂ /NSPC-based rechargeable liquid ZABs show a large open-circuit potential of 1.54 V, an ultrahigh peak power density of 181 mW cm ^-2 , an enormous capacity of 816 mAh g ^-1 , and a remarkable stability for more than 1720 discharging/charging cycles. Additionally, the assembled flexible all-solid-state ZABs also demonstrate outstanding cycle stability, surpassing 140 discharging/charging cycles. Therefore, this highly operable synthetic strategy offers substantial understanding in the development of magnificent bifunctional electrocatalysts for various sustainable energy conversions and beyond.
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