Flexible Nb2O5/MoS2/Carbon Nanofiber Paper Anodes for Sodium-Ion Batteries

Abstract

The design and fabrication of flexible anodes are crucial for advancing flexible sodium-ion batteries (SIBs). Electrospun carbon nanofiber (CNFs) composite electrodes are expected to be an effective solution. Here, by beneficial introduction of appropriate amount of Nb₂O₅ nanoparticles into pure CNFs, the problem of brittle stress concentration in CNFs has been significantly mitigated, providing good flexible mechanical stability. However, both Nb₂O₅ and pure CNFs face the issue of relatively low theoretical capacity, which limits their application in SIBs. In order to address this issue, a cattail-like flexible fiber paper anode composed of Nb₂O₅/MoS₂/C CNFs is developed and fabricated in this study. With the aid of synergetic effects, it delivers a specific capacity of 302.68 mA h g^–1 at 0.1 A g^–1 higher than that of Nb₂O₅ CNFs (156.14 mA h g^–1). Additionally, it shows the highest reversible specific capacity of 266.43 mA h g^–1 after 100 cycles at 0.1 A g^–1 higher than the contrasted Nb₂O₅ (154.09 mA h g^–1) and MoS₂ (127.37 mA h g^–1) anodes. The relevant kinetic mechanism was revealed by analyzing the pseudocapacitive sodium storage behavior and theoretical calculations. This work offers an effective strategy for developing a high-performance flexible SIB anode.