Interfacial Manipulation Enabled by Three-Dimensional Lithiophilic Nanofiber Networks toward Uniform and Bottom-Up Lithium Deposition

Anode-free lithium metal batteries (AFLMBs) are desirable candidates in the pursuit of high-energy-density rechargeable batteries, but their practical application confronts the formidable challenges involving uncontrolled growth of lithium (Li) dendrites and dissatisfactory reversibility of Li plating/stripping. Herein, an interfacial manipulation strategy enabled by three-dimensional (3D) lithiophilic nanofiber networks, fabricated through electrospinning coupled with a heat-treatment technique, was first reported toward uniform and bottom-up Li deposition for efficient AFLMBs. Significantly, the as-prepared polyvinylidene fluoride (PVDF)-incorporated oxidized polyacrylonitrile (F-OPAN) nanofibers possessed abundant polar functional groups, which were given excellent Li+ affinities to homogenize Li+ flux inside 3D scaffold and alleviate electrode volume expansion. Moreover, their lithiophilic surfaces with a low Li nucleation energy barrier and insulating 3D networks with low local current density synergistically regulated the Li nucleation and growth behaviors, manifesting fast kinetics for Li plating/stripping and guiding uniform Li nucleation/growth. Benefiting from the comodification of copper oxide (CuO) and PVDF, a stabilized and robust inorganic-rich solid electrolyte interface film was in situ constructed, which greatly facilitated interfacial charge transfer, alleviated parasitic reactions, and consolidated electrode/electrolyte interface. Furthermore, the coupled heat-treatment method effectively ensured strong adhesion between nanofiber interlayers and the Cu substrate. As validation, the resulting CuO@F-OPAN/Cu electrodes still well maintained the dendrite-free morphology under a Li deposition capacity of 2.0 mA h cm–2. The Li ∥ Cu half-cells and symmetrical cells yielded superior cycling durability and stability, even at high current densities or Li deposition amounts. More importantly, the capacity retention of the assembled LiFePO4 ∥ Cu anode-free cells was impressively improved to 49.3% after 100 cycles, charting a promising course for anode stabilization to create new opportunities for advanced AFLMBs.