Defect-Rich Nitrogen-Doped Carbon Nanofiber Networks via ZnO Volatilization for Scalable Ultrathin Lithium Metal Anode

The practical application of lithium metal anodes in next-generation high-energy-density batteries remains a significant challenge due to dendritic lithium growth and uncontrollable volume fluctuations, which compromise cycle life and safety. To address these limitations, a conductive and lithiophilic host framework is proposed based on a nitrogen-doped carbon nanofiber (N-CNF) scaffold derived from a Polyimide@zinc oxide (PAN@ZnO) precursor fabricated via a scalable electrospinning process. During high-temperature carbonization, the incorporated ZnO volatilizes, inducing nitrogen doping in the CNF matrix and generating abundant defect sites. The resulting N-CNF network provides continuous electronic pathways, enhanced lithiophilicity, and mechanical robustness, promoting uniform lithium nucleation and suppressing dendritic growth. This synergy stabilizes the lithium/electrolyte interface and accommodates volume variations during cycling, enhancing electrochemical performance under high current densities. Consequently, the optimized N-CNF from CNF@ZnO (1 wt%) exhibits a reduced lithium nucleation overpotential of ~39.6 mV, markedly lower than Cu (~126.8 mV), pristine CNF (~58.5 mV), and CNF@ZnO (0.5 wt%)-derived N-CNF (~57.6 mV), at 1 mA cm−2 and 1 mAh cm−2. The N-CNF host demonstrates dendrite-free cycling stability beyond 1400 h in symmetric cells and robust performance in full cells with NCM811 cathodes, retaining high capacity over 100 cycles at 0.3 C. This work highlights the applicability of the N-CNF scaffold on ultra-thin lithium (30–40 µm)/copper (Cu@Li) foils via a simple room-temperature compression transfer, avoiding high-temperature treatments or complex coatings. These findings highlight the potential of ZnO-assisted N-CNF frameworks as a scalable, industrially viable strategy for developing safe and durable lithium metal batteries.