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[Display omitted] • A 3D soft-rigid PVDF@SnO 2 nanofiber layer is electrospun on copper current collector. • The soft nanofiber layers realize uniform Li+ flux and dendrite-free Li deposition. • Rigid SnO 2 offers abundant Li+ nucleation sites and promotes highly stable SEI layer. • Nanofiber flexible skeleton can accommodate and mitigate electrode volume expansion. • Such soft-rigid nanofiber layers account for prolonged cycle life of Li metal cells. Lithium (Li) metal is regarded as the most desirable anode candidates for high-energy–density batteries by virtue of its lowest redox potential and ultrahigh theoretical specific capacity. However, uncontrollable Li dendritic growth, infinite volume variation and unstable solid electrolyte interface (SEI) ineluctably plague its commercialization process. Herein, the three-dimensional (3D) nanofiber functional layers with synergistic soft-rigid feature, consisting of tin oxide (SnO 2)-anchored polyvinylidene fluoride (PVDF) nanofibers, are directly electrospun on copper current collector. This strategy can effectively regulate uniform Li deposition and strengthen SEI stability through the dual effect of physical accommodation and chemical ionic intervention. On the one hand, the nanofiber interlayers with excellent electrolyte affinity and well-distributed Li+ transport pathways can promote uniform Li+ flux distribution and large-size Li deposition. On the other hand, the rigid SnO 2 contributes to reducing Li nucleation overpotential and stabilizing SEI layer assisted by its spontaneous reaction with Li. As a result, the smooth and dense Li deposition is achieved by such soft-rigid nanofiber interlayers, thereby extending the cycling life and improving the safety application of Li metal batteries. This work offers a new route for efficient protection of Li metal anodes and brings a new inspiration for developing high-energy–density Li metal batteries. [ABSTRACT FROM AUTHOR]

The atomic‐scale structure of cuprous selenide room temperature phase (α‐Cu2Se), which plays an important role in understanding the mechanism of its high thermoelectric performance, is still not fully determined. Here, direct observation with atomic‐scale resolution is realized to reveal the fine structure of α‐Cu2Se via spherical‐aberration‐corrected scanning transmission electron microscopy. It is observed to be an interesting self‐independent binary‐sublattice construction for Cu and Se in α‐Cu2Se, respectively, which shows a variety of ordered copper fluctuation structures are embedded in a rigid pseudo‐cubic Se sublattice. Ordering of Cu uses a variety of configurations with little energy difference, forming considerable amounts of "boundaries," which may lead to ultrastrong phonon scattering. Furthermore, density functional theory calculations indicate that the electronic structures are mainly determined by the rigid Se face‐centered cubic sublattice and not sensitive to the various copper fluctuations, which may guarantee the electron transfers with large carrier mobility. The self‐independent binary‐sublattice construction is speculated to enhance phonon scattering while still maintaining good electrical transport property. This study provides new critical information for further understanding the possible correlation between the specific structure and thermoelectric performance of α‐Cu2Se, as well as designing new thermoelectric materials. [ABSTRACT FROM AUTHOR]