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Interlayer transport of charges and carriers of 2D nanomaterials is a critical parameter that governs the material and device performance in energy storage applications. Inspired by multilevel natural bamboo‐membrane with ultrafast water and electrolyte transport properties to support its super‐rapid growth rate, 2D–2D multilevel heterostructured graphene‐based membranes with tailored gradient interlayer channels are rationally designed for achieving ultrafast interlayer ion transport. The bioinspired heterostructured membranes possess multilevel interlayer spacing distributions, where the closely packed layers with sub‐nanosized interlayer space provide ultrafast confined interlayer ion transport, while the loosely stacked outer layers consisting of open channels with large distances up to few micrometres are favorable for rapid wetting and penetration of liquid electrolytes. The combination of advantages of large‐size open channels and nanosized confined channels offers ultrafast electrolyte wetting and permeation and interlayer ion transport and provide the devices with superior volumetric capacity as free‐standing electrodes for rechargeable batteries.

The key point to developing green and environmentally friendly zinc-air batteries is exploring efficient bifunctional electrocatalysts for oxygen reduction and evolution reactions (ORR and OER) on an air electrode. Herein, we reported a facile and green method for fabricating a bifunctional electrocatalyst of Co@N-CNT/rGO, which is composed of cobalt nanoparticles wrapped into nitrogen-doped carbon nanotubes growing on reduced graphene oxide. It is obtained by pyrolyzing a GO-wrapped two-dimension leaf-like zeolitic imidazolate framework. The Co@N-CNT/rGO-0.1 exhibits efficient catalytic activities for ORR and OER with a small Tafel slope. It benefits from the synergistic effect of the Co nanoparticle and N-CNT, the high conductivity of reduced graphene oxide and highly graphitizing carbon nanotubes, the great specific surface area, and suitable aperture size. Moreover, the Co@N-CNT/rGO-0.1 catalyst assembled primary zinc-air battery shows a high open-circuit voltage (1.43 V), a large peak power density (122 mW cm–2), and an excellent specific capacity (855 mA h gZn –1). In addition, the Co@N-CNT/rGO-0.1 assembly rechargeable zinc-air battery also displays an excellent cycling durability of 120 h at 5 mA cm–2. According to the above results, our work provides a cost-effective strategy to scale-up and commercialize the bifunctional electrocatalysts for zinc-air battery application.

Developing efficient bifunctional electrocatalysts with excellent oxygen reduction and evolution reaction (ORR/ OER) activity to meet practical demands in Zn−air batteries (ZABs) is highly crucial and challenging. Herein, a simple hydrothermal one-step method is exploited to successfully synthesize Co 3 O 4 −NiCo 2 O 4 anchored on N-doped reduced graphene oxide nanosheets (Co 3 O 4 −NiCo 2 O 4 /N-RGO). The active sites present in Co 3 O 4 −NiCo 2 O 4 /N-RGO and the synergy between N-RGO and Co 3 O 4 −NiCo 2 O 4 accelerate the charge transfer and transport rate during the electrochemical course, which improves the ORR/OER activities of the Co 3 O 4 −NiCo 2 O 4 / N-RGO electrocatalyst. As expected, the Co 3 O 4 −NiCo 2 O 4 /N-RGO exhibits a better half-wave potential in the ORR and a lower Tafel slope during the OER process. A ZAB with optimal Co 3 O 4 −NiCo 2 O 4 /N-RGO as the cathode gives a higher open-circuit voltage (1.49 V), larger power density (97 mW cm −2 ), and better stability (180 h).

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