Two-dimensional dysprosium-modified bamboo-slip-like lithium titanate with high-rate capability and long cycle life for lithium-ion batteries

Abstract

Two-dimensional dysprosium-modified bamboo-slip-like Li₄Ti₅O₁₂ (2D Dy-B-LTO) has been synthesized by a one-pot hydrothermal method. The structure and morphology of the as-prepared materials were analyzed by X-ray diffraction (XRD) and electron microscopy. The results show that dysprosium is doped into both 8a and 16d sites of Li₄Ti₅O₁₂, which is determined by Rietveld analysis of XRD data. Dysprosium-modified Li₄Ti₅O₁₂ shows bamboo-slip-like nanosheet morphology and the possible formation mechanism is proposed. The as-prepared samples exhibit superior high-rate capability and excellent cycle performance. The initial discharge capacity of Li_4−x/3Ti_5−2x/3Dy_xO₁₂ (x = 0.02) is 181.8 mA h g⁻¹ at 20C; surprisingly, even when cycled at 100C, the discharge capacity still retains 140.9 mA h g⁻¹ after 1000 cycles. The improved electrochemical performance could be attributed to bamboo-slip-like nanosheets in conjunction with dysprosium doping, which can offer more ion and electron transporting channels and increase the amount of Ti³⁺/Ti⁴⁺ mixing as charge compensation.