1D hollow nanostructures combine the advantages of enhanced surface-to-volume ratio, short transport lengths, and efficient 1D electron transport, which can provide more design ideas for the preparation of highly active oxygen evolution (OER) electrocatalysts. A unique architecture of dual-phase octahedral CoMn O /carbon hollow nanofibers has been prepared via a two-step heat-treatment process including preoxidation treatment and Ostwald ripening process. The hollow and porous structures provide interior void spaces, large exposed surfaces, and high contact areas between the nanofibers and electrolyte and the morphology can be engineered by adjusting the heating conditions. Due to the intimate electrical and chemical coupling between the oxide nanocrystals and integrated carbon, the dual-phase octahedral CoMn O /carbon hollow nanofibers exhibit excellent OER activity with overpotentials of 337 mV at current density of 10 mA cm and Tafel slope of 82 mV dec . This approach will lead to the new perception of design issue for the nanoarchitecture with fine morphology, structures, and excellent electrocatalytic activity.

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Lithium (Li) dendrites and volume expansion during repeated Li plating and stripping processes are the major obstacles to the development of advanced Li metal batteries. Li nucleation and dendrite growth can be controlled and inhibited spatially by using 3-dimensional (3D) hosts together with efficient lithiophilic materials. To realize next-generation Li-metal batteries, it is critical to effectively regulate the surface structure of the lithiophilic crystals. Herein, exposed-edged Cu3P faceted nanoparticles anchored along the interlaced carbon nanofibers (ECP@CNF) are developed as a highly efficient 3D Li host. Through the 3D interlaced rigid carbon skeleton, volume expansion can be accommodated. The (300)-dominant edged crystal facets of Cu3P with abundant exposed P3– sites not only exhibit strong micro-structural Li affinity but also have relatively high charge transference to nucleate uniformly and effectively, resulting in reduced polarization. Consequently, under a high current density of 10 mA cm–2 with a high discharge of depth (60%), ECP@CNF/Li symmetric cells demonstrate outstanding cycling stability for 500 h with a small voltage hysteresis of 32.8 mV. Notably, the ECP@CNF/Li∥LiFePO4 full cell exhibits a more stable cycling performance for 650 cycles under a high rate of 1 C, with capacity retention up to 92% (N/P = 10, 4.7 mg cm–2 LiFePO4). Even under a limit Li (3.4 mA h) with an N/P ratio of 2 (8.9 mg cm–2 LiFePO4), ECP@CNF/Li∥LiFePO4 full cell can also demonstrate excellent reversibility and stable cycling performance with higher utilization of Li. This work provides an insight view into constructing high-performance Li-metal batteries under more strict conditions.