The synergy of 2D TMDs and carbon nanofibers in sodium ion batteries: overcoming structural challenges to enhanced columbic efficiency

Sodium-ion batteries (SIBs) have been deemed promising substitutes for lithium-ion batteries (LIBs), but challenges remain in pursuing high flexibility, high-rate performance, as well as cycling sustainability. In this work, a novel interface-coupled hybrid electrode is designed by combining atomically thin, two-dimensional (2D) transition-metal dichalcogenides (TMD) molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂) nanosheets onto carbon nanofiber (CNF) scaffolding to create a hierarchical mixed phase 2D 1D hybrid structure via precision exfoliation-deposition approaches. MoS₂-CNF (M-CNF) and WS₂-CNF (W-CNF) mixed phase (1 T/2H) hybrid nanocomposites possess controllable nanosheet thickness, defects, as well as strong interfacial interactions. The results from comprehensive characterization analysis include strong interfacial bonds, uniform nanosheet distribution, which promote electron transport routes as well as flexibility. The main findings for M-CNF showed ~673 mAh/g capacity, initial coulombic efficiency (ICE) of ~83 %, whereas W-CNF showed ~461 mAh/g capacity retention; in addition, they showed high-rate discharge capabilities with ~600 consecutive cycles collectively verifying the hypothesis of optimized interfacial interactions for charge transport as well as flexibility benefits. This study forges a new scalable mixed phase electrode platform, contributing to fundamental insights into interface-coupled hybrid in flexible energy storage technologies offering an avenue to more efficient applications for high-performance wearable SIBs.