Colloidal TiO₂ solid spheres as high-performance anodes for Lithium-ion batteries: Synthesis, characterization, and optimization

Anatase phase TiO₂ nanoparticles were successfully synthesized by annealing amorphous colloidal TiO₂ spheres. The colloidal TiO₂ nanoparticles exhibited enhanced specific discharge capacities ∼296 (0.1C), 185 (1C), 127 (2C), 101 (5C) and 82 mAh g^-1 (10C) in contrast to their amorphous counterparts ∼182 (0.1C), 119 (1C), 81 (2 C), 43 (5 C) and 18 mAh g^-1 (∼10C rates). Amorphous TiO₂ nanoparticles developed a layer of solid electrolyte interface (SEI) comprising lithium carbonate, lithium alkyl carbonates, and organic phosphates, leading to heightened intrinsic resistance of cells and diminished performance in terms of rate and cycling. Conversely, annealing at high temperatures effectively eliminates chemisorbed water and hydroxyl groups, resulting in improved stability under varying rates and during cycling for lithium-ion batteries based on titanium dioxide. The annealed colloidal TiO₂ demonstrated notably elevated specific discharge capacities and capacity retention of 93.5 % compared to amorphous titanium dioxide spheres of 42.1 %.