Plasma Etching of Flexible NiS/Carbon Nanofiber Composites for Enhanced Lithium Storage Kinetics

ABSTRACT

Flexible lithium‐ion batteries (FLIBs) require electrode materials that simultaneously integrate mechanical flexibility, high electrochemical activity, and structural robustness. In this study, a plasma etching strategy is employed to regulate electrospun NiS/carbon nanofiber (NiS/CNFs) composite membranes, yielding flexible Etch‐NiS/CNFs electrodes with tailored porous and defect‐rich interfaces. Controlled NH ₃ plasma treatment selectively removes surface amorphous carbon while preserving the interconnected carbon nanofiber conductive framework, thereby maintaining mechanical integrity and structural continuity. Consequently, the exposed NiS active phase and plasma‐induced surface defects generate a hierarchical mesoporous architecture with enhanced electrolyte accessibility. The Etch‐NiS/CNFs sample exhibits reduced charge‐transfer resistance, shortened relaxation time, and improved lithium‐ion diffusion kinetics. Benefiting from the synergistic effects of interfacial modification and structural preservation, it delivers a high reversible capacity of 670.1 mAh g ⁻¹ after 600 cycles at 1 A g ⁻¹ , along with excellent rate capability. This study presents a novel plasma‐induced porous defect strategy to enhance the performance of transition metal sulfide materials for flexible energy storage systems.