Yttrium-doped Li4Ti5O12 nanoparticles as anode for high-rate and high-energy lithium-ion batteries

Abstract

Li₄Ti₅O₁₂ (LTO) batteries are known for safety and long lifespan due to zero-strain and stable lattice. However, their low specific capacity and lithium-ion diffusion limit practical use. This study explored modifying LTO through yttrium doping by hydrothermal method to form Li₄Y_0.2Ti_4.8O₁₂ nanoparticles. This approach optimized electron and ion transport, markedly enhancing rate and cycle performance. XRD and TEM revealed that Y addition increased interplanar distance of LTO and widened Li⁺ transport pathways. XPS indicated that Y doping augmented the oxygen vacancy concentration and Ti³⁺ content. UV tests demonstrated a band gap reduction from 3.72 eV to 2.94 eV, accompanied by enhanced electronic conductivity. EIS tests showed lithium-ion diffusion coefficient remarkably increased to 1.27 × 10^–10 cm² s⁻¹_. The initial discharge capacity of Li₄Y_0.2Ti_4.8O₁₂ at 1 A g⁻¹ reached 198.9 mAh g⁻¹ and retained 89.3% capacity after 1000 cycles. At 6 A g⁻¹, the discharge capacity was 161.1 mAh g⁻¹, while at an ultra-high current density of 20 A g⁻¹, it reached 78.8 mAh g⁻¹, highlighting its robust rate performance. The yttrium-doped and nano-morphology stabilizes the LTO lattice, enhancing rate performance and cycling stability. This study reveals that LTO has the potential to be used in the high-energy fast-charging storage market.

Graphical Abstract