Search

[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]

• A dual-network structured nanofiber separator with fast ionic conductor is prepared. • This separator has well-distributed nanopore, high porosity and good heat-resistance. • LLZTO can well anchor free anions and offer fast Li+ channels to boost Li+ migration. • This separator achieves high t Li +, homogenized Li+ flux and uniform Li deposition. • Batteries with this separator show good cycle stability and high C-rate capability. Separator plays an important role in improving the long-term cycle stability and safety performance of high-energy–density lithium-metal batteries (LMBs). Herein, a robust thermotolerant separator is prepared by one-step electrospinning technique, combing fluorinated poly (m-phenylene isophthalamide) nanofibers with Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO), a fast ionic conductor. The synergistically incorporated poly (vinylidene fluoride-co-hexafluoropropylene) and LLZTO trigger off the formation of a fancy dual-network structure with high porosity and well-distributed nanopores, in which ultrafine secondary nanonets are tightly bound with three-dimensional nanofiber scaffold. LLZTO can not only provide sufficient Li+ migration channels, but also immobilize free anions to strengthen ionic transmission. Moreover, this nanofiber separator possesses high mechanical strength, excellent thermal stability and desirable electrolyte affinity. It can gel liquid electrolyte well, leading to high t Li +, homogenized Li+ flux and uniform Li deposition. Consequently, LMBs with this dual-network structured nanofiber separator deliver satisfactory cycle stability and high C-rate capability. This contribution provides new insights into the design and development of high-quality nanofiber separators for dendrite-free and high-safety LMBs. [ABSTRACT FROM AUTHOR]