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The recently emerging metal-air batteries equipped with advanced oxygen electrodes have provided enormous opportunities to develop the next generation of wearable and bio-adaptable power sources. Theoretically, neutral electrolyte-based Mg-air batteries possess potential advantages in electronics and biomedical applications over the other metal-air counterparts, especially the alkaline-based Zn-air batteries. However, the rational design of advanced oxygen electrode for Mg-air batteries with high discharge voltage and capacity under neutral conditions still remains a major challenge. Inspired by fibrous string structures of bufo-spawn, it is reported here that the scalable synthesis of atomic Fe-N coupled open-mesoporous N-doped-carbon nanofibers (OM-NCNF-FeN ) as advanced oxygen electrode for Mg-air batteries. The fabricated OM-NCNF-FeN electrodes present manifold advantages, including open-mesoporous and interconnected structures, 3D hierarchically porous networks, good bio-adaptability, homogeneously coupled atomic Fe-N sites, and high oxygen electrocatalytic performances. Most importantly, the assembled Mg-air batteries with neutral electrolytes reveal high open-circuit voltage, stable discharge voltage plateaus, high capacity, long operating life, and good flexibility. Overall, the discovery on fabricating atomic OM-NCNF-FeN electrode will not only create new pathways for achieving flexible, wearable, and bio-adaptable power sources, but also take a step towards the scale-up production of advanced nanofibrous carbon electrodes for a broad range of applications.

Producing supramolecular chirality from achiral π-conjugated polymers toward preferred chiral memory, effective circularly polarized luminescence, and chiral sensor is extremely important in design of functional chiral materials. Proposed herein is an effective protocol to generate and memorize the supramolecular chirality formed from achiral poly­(9,9-dioctyl­fluorene) (PF8) induced by chiral solvation. The process of chiral supramolecular assembly was monitored by UV–vis spectroscopy, circular dichroism (CD), and fluorescent spectroscopy. Achiral PF8 dissolved in neat (R)-(+)-limonene (1R) and (S)-(−)-limonene (1S) underwent chiral sol–gel transition at −20 °C. PF8 aggregates revealed intense CD and circularly polarized luminescence (CPL) signals due to β-phase, exhibiting absolute dissymmetry ratio of ≈2 × 10–3 at 430–470 nm. The supramolecular chirality of PF8 aggregates can be perfectly memorized in solid film even near decomposition temperature (300 °C), comparing favorably with that from chiral polyfluorene. Atomic force microscopy (AFM) inferred helically distorted PF8 aggregate motifs responsible for the CD and CPL functionality. Furthermore, the first chiral sensor to detect nonracemic limonene molecules employing achiral PF8 spin-cast film from CHCl3 solution was achieved.

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This study presents the fabrication of multifunctional nanolayers on biomedical membrane surfaces by using LBL self-assembly of nanogels and heparin-like polymers.