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 RuO, 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, a specific capacity of 830 mA h g, and better durability for 210 h after mechanical recharging. An extraordinary small charge-discharge voltage polarization (∼0.80 V at 25 mA cm), 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.

CuCo2S4 Nanosheets@N‐Doped Carbon Nanofibers by Sulfurization at Room Temperature as Bifunctional Electrocatalysts in Flexible Quasi‐Solid‐State Zn–Air Batteries

“…[10,45] As expected, there is a lower overpotential (315 mV) required for CuCo 2 S 4 NSs@N-CNFs to reach a current density of 10 mA cm −2 (Figure 3d), which is outstandingly 81 mV lower than that of the CuCo 2 O 4 NPs@N-CNFs (396 mV) (Table S2, Supporting Information). [10,45] As expected, there is a lower overpotential (315 mV) required for CuCo 2 S 4 NSs@N-CNFs to reach a current density of 10 mA cm −2 (Figure 3d), which is outstandingly 81 mV lower than that of the CuCo 2 O 4 NPs@N-CNFs (396 mV) (Table S2, Supporting Information).…”

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ZABs) have acquired enormous attention because of their high theoretical energy density (1370 W h kg −1 ), abundant lowcost resources for the starting materials required, and high device safety. [9][10][11][12][13][14][15][16][17][18] For this purpose, several types of cathode materials have been explored. [9][10][11][12][13][14][15][16][17][18] For this purpose, several types of cathode materials have been explored.

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Carbon-Based Metal-Free Electrocatalysis for Energy Conversion, Energy Storage, and Environmental Protection

“…7a) [28]. Furthermore, N,S-co-doped graphene microwires were used as an air cathode in a Zn-air battery and displayed a low overpotential of 0.31 V at 10 mA cm −2 and a high Faradic efficiency (FE) of 95% for OER [183].…”

“…Because ORR, OER, and HER have been reviewed in several previously published articles [4,[10][11][12], the focus in this review will be on recent advances and new reactions (e.g., CO 2 RR, multifunctional electrocatalysis). A critical overview of efficient methods for developing carbon-based metal-free catalysts for various energy conversion/storage and environmental protection devices, including ORR in fuel cells [13][14][15][16][17], ORR and OER in metal-air batteries [18][19][20][21][22][23][24][25][26][27][28], OER and HER in water-splitting units [29][30][31], I − /I 3− reduction in dye-sensitized solar cells [32][33][34][35], and CO 2 RR in Li-CO 2 batteries [36][37][38][39][40][41][42] will then be provided. Finally, perspectives and challenges in this fast-growing and significant field are outlined.…”

Stable and Efficient Nitrogen‐Containing Carbon‐Based Electrocatalysts for Reactions in Energy‐Conversion Systems

“…[24] Chen and co-workersr eport the doping of S, B, and Ps eparately into g-CN, and then couple these materials with porous carbon to improvec onductivity. [26] The increasei n the conductivity is attributed to modulation of the electronic properties and enhanced delocalization of the p bonds over the plane of g-CN induced by dual doping of Pa nd Sr ather than coupling with the conductive substrates. [25] Lee et al propose that S,P-dual-doped g-CN exhibits greater electrocatalytic activity than other candidates.…”