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With the rapid development of portable and wearable electronics, safety concerns over flexible energy devices are inevitable. Therefore, it is important to develop energy supplies that are safe for use. In this work, a highly safe, durable, adaptable, and flexible air‐breathing direct methanol fuel cell (DMFC) is successfully prepared by synthesizing and applying a new composite material with agar gel and wood sponge, that is, a gel/sponge composite. The gel/sponge composite has a high absorption rate, high cyclic performance, high methanol absorption capacity, high energy content, and high flexibility. Moreover, the gel/sponge composite with 1.5% agar gel retains approximately 90% of the methanol solution at a pressure of 29.4 kPa, and the areal energy density of the proposed DMFC approaches 13.7 mWh cm−2. Both the single‐cell and stack of DMFC with the new composite material successfully survive a series of destructive tests, including needle penetration, cutting, and compression. Therefore, it is successfully demonstrated that absorbent materials can greatly boost the safety, adaptability, flexibility, and energy density of air‐breathing DMFCs. Furthermore, this concept shows promise in improving the safety of other fuel cells by using absorbent materials to solidify their gaseous or liquid fuels.

Hierarchically patterned proton-exchange membranes (PEMs) have the potential to significantly increase the specific surface area, thus improving the catalyst utilization rate and performance of proton-exchange membrane fuel cells (PEMFCs). In this study, we are inspired by the unique hierarchical structure of the lotus leaf and proposed a simple three-step strategy to prepare a multiscale structured PEM. Using the multilevel structure of the natural lotus leaf as the original template, and after structural imprinting, hot-pressing, and plasma-etching steps, we successfully constructed a multiscale structured PEM with a microscale pillar-like structure and a nanoscale needle-like structure. When applied in a fuel cell, the multiscale structured PEM resulted in a 1.96-fold increase in discharge performance and a significant improvement in mass transfer compared to the membrane electrode assembly (MEA) with a flat PEM. The multiscale structured PEM has the combined advantage of a nanoscale and a microscale structure, benefiting from the markedly reduced thickness, increased surface area, and improved water management inherited from the multiscale structured lotus leaf’s superhydrophobic characteristic. Using a lotus leaf as a multilevel structure template avoids the complex and time-consuming preparation process required by commonly used multilevel structure templates. Moreover, the remarkable architecture of biological materials can inspire novel and innovative applications in many fields through nature’s wisdom.

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The commercialization of fuel cells inevitably brings recycling problems. Therefore, achieving high recyclability of fuel cells is particularly important for their sustainable development. In this work, a recyclable standalone microporous layer (standalone MPL) with interpenetrating network that can significantly enhance the recyclability and sustainability of fuel cells is prepared. The interpenetrating network enables the standalone MPL to have high strength (17.7 MPa), gas permeability (1.55 × 10−13 m2), and fuel‐cell performance (peak power density 1.35 W cm−2), providing the basic guarantee for its application in high‐performance and highly recyclable fuel cells. Additionally, the standalone MPL is highly adaptable to various gas‐diffusion backings (GDBs), providing high possibility to select highly recyclable GDBs. Outstandingly, anode standalone MPLs and GDBs can be easily detached from the spent membrane electrode assembly (MEA). This not only saves >90 vol% solvent in the recovery of the catalyst‐coated membrane (CCM), but also extends the service life of the GDBs and the anode standalone MPL at least 138 times (2 760 000 h assuming 20 000 h of CCM) comparing to CCM. Therefore, the standalone MPL significantly enhances the recyclability and sustainability of fuel cells and is promising to be an indispensable component in the next‐generation fuel cells.

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