Porous NaTi₂(PO₄)₃/C Hierarchical Nanofibers for Ultrafast Electrochemical Energy Storage

NaTi₂(PO₄)₃ (NTP) with a sodium superionic conductor three-dimensional (3D) framework is a promising anode material for sodium-ion batteries (SIBs) because of its suitable potential and stable structure. Although its 3D structure enables high Na-ion diffusivity, low electronic conductivity severely limits NTP's practical application in SIBs. Herein, we report porous NTP/C nanofibers (NTP/C-NFs) obtained via an electrospinning method. The NTP/C-NFs exhibit a high reversible capacity (120 mA h g^-1 at 0.2 C) and a long cycling stability (a capacity retention of ∼93% after 700 cycles at 2 C). Furthermore, sodium-ion full cells and hybrid sodium-ion capacitors have also been successfully assembled, both of which exhibit high-rate capabilities and remarkable cycling stabilities because of the high electronic/ionic conductivity and impressive structural stability of NTP/C-NFs. The results show that the nanoscale-tailored NTP/C-NFs could deliver new insights into the design of high-performing and highly stable anode materials for room-temperature SIBs.