Self-Supporting and Binder-Free Anode Film Composed of Beaded Stream-Like Li₄Ti₅O₁₂ Nanoparticles for High-Performance Lithium-Ion Batteries

A self-supporting film composed of arrays of Li₄Ti₅O₁₂ (LTO) nanoparticles (NPs) prepared through chemical lithiation of anodic TiO₂ nanotube arrays and calcination in air is used as a high-performance binder-free anode in lithium-ion batteries (LIBs). The LTO nanoparticles formed in situ are closely connected along the axial direction of the pristine TiO₂ nanotubes, forming a beaded stream-like structure. The self-supporting NPs film has a large tap density and overall packing factor, and the three-dimensional (3D) network of NPs increases the electroactive interface, facilitating transfer of Li⁺ and enhancing the intercalation kinetics during charging/discharging. The LTO electrode with excellent mechanical flexibility and robustness has a volumetric capacity of 304 mAh cm⁻³ at a current density of 50 mA cm⁻³ as well as a high rate capability of 208 mAh cm⁻³ at 5000 mA cm⁻³. After undergoing 500 cycles at a high current density of 1250 mA cm⁻³, 91.4 % of the capacity is retained, demonstrating high reversibility and cycling stability of the binder-free LTO NPs film electrode in LIBs.