title: Scalable 3-D Carbon Nitride Sponge as an Efficient Metal-Free Bifunctional Oxygen Electrocatalyst for Rechargeable Zn-Air Batteries.
abstract: Rational design of efficient and durable bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is critical for rechargeable metal-air batteries. Here, we developed a facile strategy for fabricating three-dimensional phosphorus and sulfur codoped carbon nitride sponges sandwiched with carbon nanocrystals (P,S-CNS). These materials exhibited high surface area and superior ORR and OER bifunctional catalytic activities than those of Pt/C and RuO2, respectively, concerning its limiting current density and onset potential. Further, we tested the suitability and durability of P,S-CNS as the oxygen cathode for primary and rechargeable Zn-air batteries. The resulting primary Zn-air battery exhibited a high open-circuit voltage of 1.51 V, a high discharge peak power density of 198 mW cm-2, a specific capacity of 830 mA h g-1, and better durability for 210 h after mechanical recharging. An extraordinary small charge-discharge voltage polarization (∼0.80 V at 25 mA cm-2), superior reversibility, and stability exceeding prolonged charge-discharge cycles have been attained in rechargeable Zn-air batteries with a three-electrode system. The origin of the electrocatalytic activity of P,S-CNS was elucidated by density functional theory analysis for both oxygen reactions. This work stimulates an innovative prospect for the enrichment of rechargeable Zn-air battery viable for commercial applications such as armamentaria, smart electronics, and electric vehicles.
authors.affiliation: Department of Materials and Chemical Engineering, ‡Department of Bionano Technology, and §Department of Applied Chemistry, Hanyang University , Ansan, Kyunggido 426-791, Republic of Korea.
authors.forename: Sambhaji S
authors.initials: SS
authors.lastname: Shinde
authors.affiliation: Department of Materials and Chemical Engineering, ‡Department of Bionano Technology, and §Department of Applied Chemistry, Hanyang University , Ansan, Kyunggido 426-791, Republic of Korea.
authors.forename: Chi-Ho
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Materials and Chemical Engineering, ‡Department of Bionano Technology, and §Department of Applied Chemistry, Hanyang University , Ansan, Kyunggido 426-791, Republic of Korea.
authors.forename: Abdul
authors.initials: A
authors.lastname: Sami
authors.affiliation: Department of Materials and Chemical Engineering, ‡Department of Bionano Technology, and §Department of Applied Chemistry, Hanyang University , Ansan, Kyunggido 426-791, Republic of Korea.
authors.forename: Dong-Hyung
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Materials and Chemical Engineering, ‡Department of Bionano Technology, and §Department of Applied Chemistry, Hanyang University , Ansan, Kyunggido 426-791, Republic of Korea.
authors.forename: Sang-Uck
authors.initials: SU
authors.lastname: Lee
authors.affiliation: Department of Materials and Chemical Engineering, ‡Department of Bionano Technology, and §Department of Applied Chemistry, Hanyang University , Ansan, Kyunggido 426-791, Republic of Korea.
authors.forename: Jung-Ho
authors.identifier: 0000-0002-6731-3111
authors.initials: JH
authors.lastname: Lee
keywords: Zn−air battery; aminoguanidine; bifunctional oxygen electrocatalyst; carbon nitride sponge; phosphorus and sulfur