A Random-Aligned Carbon Nanofiber Interface Enhancing the Intrinsic Electric Field for High-Performance Lithium Metal Batteries.

Abstract

Dendrite growth and interfacial side reactions severely impair the stability of lithium negative electrodes. A deeper understanding of the structure-performance relationship between current collectors (CCs) and lithium deposition is crucial for addressing these challenges. In this study, a "random-to-aligned hierarchical porous carbon nanofibers" (r/a-HPCNFs) CC strategy was proposed to realize uniform bottom-up lithium-ion (Li⁺) deposition by analyzing the ion transport within aligned CNF channels. By constructing a top-random/bottom-aligned interface with different charge centers, the dielectric constant can be effectively adjusted, thereby promoting a polarization transformation of the intrinsic electric field and strengthening the driving force for Li⁺ migration toward the bottom of the CC. The symmetric cell assembled with Li-predeposited r/a-HPCNFs operates stably for over 6500 h at 5 mA cm^-2. With less Li predeposition (∼3 mAh, N/P = 2), r/a-HPCNF-based full cells (LiFePO₄, LiNi_0.8Co_0.1Mn_0.1O₂, and sulfur) deliver >80% capacity over 400, 260, and 200 cycles at 3, 2, and 0.5 C, respectively. These results highlight the key role of the random-aligned hierarchical architecture in intrinsic field regulation, enabling dendrite suppression and stable cycling.