1 research outputs found
Enhanced Electrochemical Performance of Rare-Earth Metal-Ion-Doped Nanocrystalline Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> Electrodes in High-Power Li-Ion Batteries
A comprehensive and comparative exploration research
performed,
aiming to elucidate the fundamental mechanisms of rare-earth (RE)
metal-ion doping into Li4Ti5O12 (LTO),
reveals the enhanced electrochemical performance of the nanocrystalline
RE-LTO electrodes in high-power Li-ion batteries. Pristi ne Li4Ti5O12 (LTO) and rare-earth metal-doped
Li4–x/3Ti5–2x/3LnxO12 (RE-LTO
with RE = Dy, Ce, Nd, Sm, and Eu; x ≈ 0.1)
nanocrystalline anode materials were synthesized using a simple mechanochemical
method and subsequent calcination at 850 °C. The X-ray diffraction
(XRD) patterns of pristine and RE-LTO samples exhibit predominant
(111) orientation along with other characteristic peaks corresponding
to cubic spinel lattice. No evidence of RE-doping-induced changes
was seen in the crystal structure and phase. The average crystallite
size for pristine and RE-LTO samples varies in the range of 50–40
nm, confirming the formation of nanoscale crystalline materials and
revealing the good efficiency of the ball-milling-assisted process
adopted to synthesize nanoscale particles. Raman spectroscopic analyses
of the chemical bonding indicate and further validate the phase structural
quality in addition to corroborating with XRD data for the cubic spinel
structure formation. Transmission electron microscopy (TEM) reveals
that both pristine and RE-LTO particles have a similar cubic shape,
but RE-LTO particles are better interconnected, which provide a high
specific surface area for enhanced Li+-ion storage. The
detailed electrochemical characterization confirms that the RE-LTO
electrodes constitute promising anode materials for high-power Li-ion
batteries. The RE-LTO electrodes deliver better discharge capacities
(in the range of 172–198 mAh g–1 at 1C rate)
than virgin LTO (168 mAh g–1). Among them, Eu-LTO
provides the best discharge capacity of 198 mAh g–1 at a 1C rate. When cycled at a high current rate of 50C, all RE-LTO
electrodes show nearly 70% of their initial discharge capacities,
resulting in higher rate capability than virgin LTO (63%). The results
discussed in this work unfold the fundamental mechanisms of RE doping
into LTO and demonstrate the enhanced electrochemical performance
derived via chemical composition tailoring in RE-LTO
compounds for application in high-power Li-ion batteries