Na2Ti3O7 Nanotubes as Anode Materials for Sodium-ion Batteries and Self-powered Systems

Graphical Na 2 Ti 3 O 7 nanotubes prepared by a hydrothermal method are used as anode materials for sodium-ion batteries (SIBs), showing a reversible discharge capacity of 126.2 mAh g −1 at 100 mA g −1 and an excellent cycling performance. Solid-state SIBs containing these nanotube anodes and an Na 3 Zr 2 Si 2 PO 12 solid electrolyte show a performance that is comparable to that of batteries containing a liquid electrolyte. Moreover, the prepared solid-state SIBs can store mechanical energy harvested by triboelectric nanogenerators (TENGs). Na 2 Ti 3 O 7 (NTO) is a potential anode material with low discharge voltage for room-temperature sodium-ion batteries. In this work, NTO nanotubes were prepared by a hydrothermal method. XRD, SEM, TEM, and HRTEM studies are performed to investigate the composition, morphology, and structure. As anodes for sodium-ion batteries, NTO nanotubes show a reversible capacity of 126.2 mAh g −1 at 100 mA g −1 . The discharge capacity can still reach 109 mAh g −1 even for 2000 cycles. Solid-state sodium-ion batteries containing NTO-nanotube anodes and an Na 3 Zr 2 Si 2 PO 12 solid electrolyte display a comparable performance to batteries with a liquid electrolyte. Moreover, the prepared solid-state sodium battery is also demonstrated to store mechanical energy harvested by triboelectric nanogenerators (TENGs). The discharge capacity reaches 121 mAh g −1 at 5 mA g −1 .