Atomic Pt with Trapped Interstitial F in PtCo Nanosheets for Zinc-Air Batteries

Platinum group metals (PGMs) based materials are currently dominantly used as oxygen reduction/evolution reaction (ORR/OER) catalysts in many emerging renewable energy devices such as Zn-air batteries (ZABs) because of their favorable surface electronic structures for electrocatalytic reactions. Most recently, atomic PGMs anchored on the conducting supports have been recognized as the most effective way to improve the utilization efficiency of PGMs and reduce the catalyst cost. However, traditional synthetic approaches to atomic catalysts, such as wet impregnation and atomic layer deposition, still have a long way to be optimized for industrial mass production. In this work, we designed a scalable and repeatable synthesis of atomic Pt in the alloyed platinum cobalt (PtCo) nanosheets by combining bottom-up electrodeposition and top-down fluorine-plasma (F-plasma) etching treatments. The interstitial F atoms trapped in the alloyed PtCo crystal structure induce lattice distortion which plays a crucial role in stabilizing the atomic Pt on the surface of catalyst (denotes as SA-PtCoF) by balancing surface free energy. Moreover, the proposed SA-PtCoF nanosheets are additive-free catalysts with abundant active sites and high surface areas, which show significant advantages over powder catalysts for ZAB due to the suppressed catalyst deactivations. Benefiting from the catalyst-support interactions and synergistic effects of SA-PtCoF, an unprecedented ZAB performance (power density of 125 mW cm -2 , capacity of 808 mAh g Zn -1 , cycle life over 240 h) is achieved, superior to commercial Pt/C@RuO 2 and other state-of-the-art ORR/OER catalysts.