Sulfurated Metal-Organic Framework-Derived Nanocomposites for Efficient Bifunctional Oxygen Electrocatalysis and Rechargeable Zn- Air Battery

The development and rational design of highly efficient and Earth-abundant bifunctional nanomaterials for electrocatalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) act as pivotal roles for the practical applications of rechargeable metal-air batteries. In this article, a Ni-Co-derived metal-organic framework (Ni-Co-MOF) is rapidly formed at ambient temperature, followed by a low-temperature sulfuration process to obtain Ni-Co-based sulfides couple with a nitrogen (N) and sulfur (S)-codoped carbon support with a porous structure (Ni-Co-S/NSC). The designed Ni-Co-S/NSC presents excellent electrocatalytic performances for OER (10 mA cm(-2) @309 mV) and ORR (0.81 V g E-1/2) and a small Delta E (Delta E = E-j10 - E-1/2) of 0.73 V in an alkaline electrolyte, enabling its use as an outstanding cathode in rechargeable Zn-air batteries. In situ Raman spectra demonstrated that metal hydroxides formed during OER endowed the obtained electrocatalyst with a predominant catalytic performance. Impressively, a homemade rechargeable Zn- air battery composed by this nanocomposite as the cathode delivered remarkable properties with a peak power density of 137 mW cm(-2) and a high specific capacity of 829 mAh g(-1). The battery also demonstrated outstanding long-term stability with a well-maintained porous structure and crystal structure.