The ability to craft high-performance and cost-effective bifunctional oxygen catalysts opens up pivotal perspectives for commercialization of zinc-air batteries (ZABs). Despite recent grand advances in the development of synthetic techniques,...
The past several years have witnessed a rapid development of intelligent wearable devices. However, despite the splendid advances, the creation of flexible human-machine interfaces that synchronously possess multiple sensing capabilities, wearability, accurate responsivity, sensitive detectivity, and fast recyclability remains a substantial challenge. Herein, a convenient yet robust strategy is reported to craft flexible transient circuits via stencil printing liquid metal conductor on the water-soluble electrospun film for human-machine interaction. Due to the inherent liquid conductor within porous substrate, the circuits feature high-resolution, customized patterning viability, attractive permeability, excellent electroconductivity, and superior mechanical stability. More importantly, such circuits display appealing noncontact proximity capabilities while maintaining compelling tactile sensing performance, which is unattainable by traditional systems with compromised contact sensing. As such, the flexible circuit is utilized as wearable sensors with practical multifunctionality, including information transfer, smart identification, and trajectory monitoring. Furthermore, an intelligent human-machine interface composed of the flexible sensors is fabricated to realize specific goals such as wireless object control and overload alarm. The transient circuits are quickly and efficiently recycled toward high economic and environmental values. This work opens vast possibilities of generating high-quality flexible and transient electronics for advanced applications in soft and intelligent systems.
The ability to craft high‐efficiency and non‐precious bifunctional oxygen catalysts opens an enticing avenue for the real‐world implementation of metal‐air batteries (MABs). Herein, Co3O4 encapsulated within nitrogen defect‐rich g‐C3N4 (denoted Co3O4@ND‐CN) as a bifunctional oxygen catalyst for MABs is prepared by graphitizing the zeolitic imidazolate framework (ZIF)‐67@ND‐CN. Co3O4@ND‐CN possesses superb bifunctional catalytic performance, which facilitates the construction of high‐performance MABs. Concretely, the rechargeable zinc‐air battery based on Co3O4@ND‐CN shows a superior round‐trip efficiency of ≈60% with long‐term durability (over 340 cycles), exceeding the battery with the state‐of‐the‐art noble metals. The corresponding lithium‐oxygen battery using Co3O4@ND‐CN exhibits an excellent maximum discharge/charge capacity (9838.8/9657.6 mAh g−1), an impressive discharge/charge overpotential (1.14 V/0.18 V), and outstanding cycling stability. Such compelling electrocatalytic processes and device performances of Co3O4@ND‐CN originate from concurrent compositional (i.e., defect‐engineering) and structural (i.e., wrinkled morphology with abundant porosity) elaboration as well as the well‐defined synergy between Co3O4 and ND‐CN, which produce an advantageous surface electronic environment corroborated by theoretical modeling. By extension, a rich diversity of other metal oxides@ND‐CN with adjustable defects, architecture, and enhanced activities may be rationally designed and crafted for both scientific research on catalytic properties and technological development in renewable energy conversion and storage systems.
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