Densely colonized isolated Cu-N single sites for efficient bifunctional electrocatalysts and rechargeable advanced Zn-air batteries

By Nayantara K. Wagh, S. Shinde, C. Lee, Jin-Young Jung, Dong-Hyung Kim, Sung-Hae Kim, Chao Lin, Sang Uck Lee, Jung‐Ho Lee. 2020

144 citations recorded by the source corpus.

Abstract The rational design of earth-abundant, highly efficient, and robust bifunctional oxygen electrocatalysts remains a contemporary challenge toward the widespread implementation of reversible metal-air batteries and fuel cells. Here, we report a universal strategy for the fabrication of single-atom (Cu, Co, and Fe) incorporated hollow nano-spheroids of nitrogen-deficient carbon nitride frameworks (CuSA@HNCNx. The interconnected three-dimensional 3D porous and hollow robust single-atom spheroid frameworks display a high surface area of 1286 m2 g−1, favorable electronic structure, local chemical coordination, effective density of active sites (Cu-Nx, pyridinic, graphitic C N etc.), and mass transport pathways. The obtained CuSA@HNCNx exhibited outstanding bifunctional reversible electrocatalytic activity and robustness for oxygen reduction and evolution reactions (ORR half-wave potential of 0.91 V, OER overpotential of 1.55 V at 10 mA cm-2, ΔE = 0.64 V, 5000 cycles), outperforming benchmarked Pt/C and RuO2. Electrocatalytic activity towards ORR/OER was analyzed by d -band center correlation using density functional theory (DFT) calculations. Moreover, reversible alkaline Zn-air batteries with the designed CuSA@HNCNx cathode illustrated a high power 212 mW cm-2, high energy density 1031 Wh kgZn−1, and excellent discharge-charge cycle life of 1800 cycles for 300 h @10 mA cm-2 with voltaic efficiency of 64.51 %. Notably, all-solid-state flexible ZABs showed long cycle life of 250 h with 1500 cycles at 25 mA cm-2 with efficiency of 66.31 %. This unique strategy offers controlled design of entangled single-atom frameworks as advanced cathodes for next-generation energy storage technology.

Subfields: Electrical and Electronic Engineering, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/fc183d4d77b41f405257fa6966332a8e04f0b7f8