Super-assembled compressible carbon frameworks featuring enriched heteroatom defect sites for flexible Zn–air batteries

• Published in: NPG Asia materials Vol. 15; no. 1; pp. 15 - 11
• Main Authors: Pang, Huaipeng, Wang, Meng, Sun, Peipei, Zhang, Wenshuai, Wang, Dan, Zhang, Runhao, Qiao, Li, Wang, Weijie, Gao, Meng, Li, Yong, Chen, Jiang, Liang, Kang, Kong, Biao
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 31.03.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/146; 639/301/299/891; 639/301/357; Biomaterials; Carbon; Carbon nanotubes; Cathodes; Chemical reduction; Chemistry and Materials Science; Compressibility; Cycles; Defects; Discharge; Electric potential; Electrocatalysts; Electrodes; Electronic devices; Energy storage; Energy Systems; Flexibility; Materials Science; Metal air batteries; Optical and Electronic Materials; Oxygen reduction reactions; Stability; Structural Materials; Surface and Interface Science; Thin Films; Voltage; Wearable technology; Zinc-oxygen batteries
• ISSN: 1884-4057; 1884-4049; 1884-4057
• DOI: 10.1038/s41427-022-00446-9

Flexible Zn–air batteries (FZABs) exhibit low cost and inherent safety and have potential for application in wearable electronic devices. Nevertheless, balancing the high energy density and flexibility of the self-supported electrodes in FZABs is still a challenge. Herein, we develop a novel superassembly strategy for the preparation of N, S-codoped porous carbon frameworks (NS@CFs) as cathodes in FZABs. Benefiting from the abundant heteroatom defect sites, NS@CF exhibits excellent electrocatalytic performance for the oxygen reduction reaction (ORR), including high electrochemical activity and long-term stability. When used as the cathode in a liquid flowing ZAB, NS@CF exhibited a power density of 221 mW cm −2 and achieved a 60% improvement over Pt/C-based ZABs. This new ZAB exhibited a high specific capacity of 792 mA h g Zn −1 , excellent long-term durability and cycling stability, which is superior to those of ZABs assembled with commercial Pt/C cathodes. In addition, the flexible NS@CF with directional channels can be used as independent air cathodes for FZABs, where it provides small charge/discharge voltage gaps, a power density of 49 mW cm −2 and outstanding cycling stability. This work provides a novel strategy for designing and fabricating highly efficient integrated electrodes for flexible and wearable electrochemical devices. In this work, we developed a novel fabrication strategy to construct elastic carbon framework electrocatalysts using nanocellulose fibers (CNFs) and carbon nanotubes (CNTs) by directional freeze casting and interfacial assembly to prepare self-supporting flexible air electrodes. The obtained carbon framework has a directional porous structure, and N and S heteroatoms are uniformly doped in the carbon skeleton, showing excellent mechanical flexibility and excellent ORR performance. Moreover, we assembled an all-solid-state flexible zinc-air battery (FZAB), offering a smaller charge/discharge voltage gap and excellent cycling stability. These results demonstrate the potential of flexible carbon frameworks for the utilization and modification of flexible energy storage devices.