Purified Molybdenite Encapsulated in N-doped Carbon Nanofibers as Binder-Free Anodes for Flexible Lithium-Ion Hybrid Capacitors

Abstract

Molybdenite possesses high natural abundance and a high theoretical lithium storage capacity but is limited by its low intrinsic conductivity and volume expansion during cycling. Herein, a flexible and binder-free anode is designed by encapsulating purified molybdenite nanosheets within nitrogen-doped carbon nanofibers (MoS2@CNF) via a scalable electrospinning and carbonization process. The unique "necklace-like" structure, in which MoS2 nanosheets are uniformly embedded within interconnected conductive CNFs, not only exposes abundant active sites but also enhances both electrical conductivity and mechanical stability. The delicate nanostructure of MoS2@CNF facilitates rapid ion/electron transport and alleviates the volume stress of MoS2 during electrochemical processes, consequently contributing to its outstanding rate capability (544.0 mAh g−1 at 2 A g−1) and excellent cycling performance (716.9 mAh g−1 after 500 cycles at 1 A g−1). The MoS2@CNF anode is further coupled with a flexible cathode (activated carbon casted onto CNF) to construct the lithium-ion hybrid capacitor, which achieves high energy and power density (84.3 Wh kg−1 at 10 kW kg−1) while demonstrates negligible capacity decay even under harsh bending conditions. This work provides a cost-effective strategy for transforming natural ore into high-performance electrodes for flexible energy storage.