Nanoflowers-like LiTi₂(PO₄)₃ on carbon nanotube fibers as novel binder-free anodes for high-performance fiber-shaped aqueous rechargeable lithium-ion batteries

NASICON-type LiTi₂(PO₄)₃ (LTP) shows tremendous potential for applications in aqueous rechargeable lithium-ion batteries (ARLIBs) due to its three-dimensional open-framework and flat voltage platform. Unfortunately, conventional solid-phase reactions and high-temperature calcination methods are unable to meet the demand for self-standing electrodes for flexible wearable ARLIBs. Herein, we develop a simple and effective one-step solvothermal method to grow nanoflowers (NFs)-like LTP directly on carbon nanotube fibers (CNTFs) as binder-free anodes for fiber-shaped ARLIBs (FARLIBs) without additional high-temperature treatment. Benefitting from the robust adhesion of the active material to the substrate and binder-free feature, the prepared LTP NFs/CNTF anode provides a high reversible volume capacity of 85.2 mAh cm⁻³ at a current density of 0.4 A cm⁻³. The quasi-solid-state FARLIB is successfully assembled by binder-free cathode coupling with LiMn₂O₄ nanowall arrays directly grown on CNTF, achieving a high capacity of 58.3 mAh cm⁻³ at a current density of 0.4 A cm⁻³ and exhibiting an encouraging 92.3 mWh cm⁻³ maximum energy density. This work provides an effective strategy for the design of novel binder-free electrodes for next-generation wearable FARLIBs.