T3C2Tx boost SnSbS composited carbon fibers achieved fast and stable free-standing quasi-solid sodium full-battery

Low energy density remains a major obstacle limiting the development and application of flexible sodium-ion batteries (SIB). Thus, this study aimed to eliminate non-active materials in electrodes, which can be a feasible way to increase the energy density of SIBs. An anode made up of flexible, free-standing SnS2/Sb2S3/Ti3C2Tx composite carbon nanofibers (SnSbS/T-M@CNF), a Na3V2(PO4)3 composite carbon nanofibers cathode (NVP@CNF), and composite gel polymer fiber electrolytes (CGPFE) were successfully synthesized through electrospinning. MXene nanosheets improved the electrical conductivity of the SnSbS/T-M@CNF electrode and absorbed sodium sulfide, inhibiting the loss of S during the reaction. Consequently, the SnSbS/T-M@CNF free-standing electrode could be stably cycled for 1000 cycles at a current density of 1 A g−1 and maintained a reversible capacity of 397.6 mAh g−1. Further, the NVP@CNF cathode and CGPFE quasi-solid electrolyte half-cells had an excellent cycle stability and rate performance. The flexible, free-standing SnSbS/T-M@CNF anode and NVP@CNF cathode were assembled into quasi-solid-state full cells to test their application value. The SnSbS/T-M@CNF||CGPFE||NVP@CNF full cell had a very low resistance and could easily power a 3 V LED chest lamp. After 500 cycles, it maintained a discharge capacity of 153 mAh g−1 under a current density of 0.5 A g−1.