Probing the Physicochemical Behavior of Variously Doped Li₄Ti₅O₁₂Nanoflowers

Abstract

This study thoroughly investigated the synthesis of not only 4 triply-doped metal oxides but also 5 singly-doped analogues of Li4Ti5O12 for electrochemical applications. In terms of synthetic novelty, the triply-doped materials were fabricated using a relatively facile hydrothermal method for the first-time, involving the simultaneous substitution of Ca for the Li site, Ln (i.e., Dy, Y, or Gd) for the Ti site, and Cl for the O site. Based on XRD, SEM, and HRTEM-EDS measurements, the resulting materials, incorporating a relatively homogeneous and uniform dispersion of both the single and triple dopants, exhibited a micron-scale flower-like morphology that remained apparently undamaged by the doping process. Crucially, the surface chemistry of all of the samples was probed using XPS in order to analyze any nuanced changes associated with either the various different lanthanide dopants or the identity of the metal precursor types involved. In the latter case, it was observed that the use of a nitrate salt precursor versus that of a chloride salt enabled not only a higher lanthanide incorporation but also the potential for favorable N-doping, all of which promoted a concomitant increase in conductivity due to a perceptible increase in Ti3+ content. In terms of the choice of lanthanide system, it was observed via CV analysis that dopant incorporation generally (albeit with some notable exceptions, especially with Y-based materials) led to the formation of higher amounts of Ti3+ species within both the singly and triply-doped materials, which consequentially led to the potential for increased diffusivity and higher mobility of Li+ species with the possibility for enabling greater capacity within these classes of metal oxides.

Enhanced Electrochemical Performance of Rare-Earth Metal-Ion-Doped Nanocrystalline Li4Ti5O12Electrodes in High-Power Li-Ion Batteries

“…Randles plots Z ′ vs ω –1/2 , as well as the Warburg factor (σ w , eq S5) representing the mass-controlled process, are illustrated in Figure b. The apparent chemical diffusion coefficients can be calculated according to eq D Li = R 2 T 2 2 A 2 n 4 C Li 2 σ 2 …”

Fabrication of Li4Ti5O12 (LTO) as Anode Material for Li-Ion Batteries

“…1D LTO nanomaterials are composed of nanorods [ 122 , 123 , 124 , 125 , 126 , 127 ], nanowires [ 128 , 129 , 130 , 131 , 132 ], nanofibers [ 95 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 ], nanotubes [ 54 , 141 ], nanoflakes [ 142 ], and nanobelts [ 143 , 144 , 145 , 146 ]. 2D LTO nanomaterials encompass nanosheets [ 136 , 147 , 148 , 149 , 150 , 151 ], nanoplates [ 152 ], and wave-like structures [ 153 ]. 3D LTO nanomaterials include nanoflowers [ 153 ], nanoporous structures [ 55 , 154 , 155 , 156 , 157 ], mesoporous structures [ 67 ], hierarchical structures [ 158 ], and nanoarrays [ 159 , 160 , 161 , 162 , 163 ,…”

“…2D LTO nanomaterials encompass nanosheets [ 136 , 147 , 148 , 149 , 150 , 151 ], nanoplates [ 152 ], and wave-like structures [ 153 ]. 3D LTO nanomaterials include nanoflowers [ 153 ], nanoporous structures [ 55 , 154 , 155 , 156 , 157 ], mesoporous structures [ 67 ], hierarchical structures [ 158 ], and nanoarrays [ 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 ].…”

“…2D LTO nanomaterials encompass nanosheets [136,[147][148][149][150][151], nanoplates [152], and wave-like structures [153]. 3D LTO nanomaterials include nanoflowers [153], nanoporous structures [55,[154][155][156][157], mesoporous structures [67], hierarchical structures [158], and nanoarrays [159][160][161][162][163][164][165][166][167][168][169]. Currently, the growth of LTO nano-powders is achieved by using successive techniques, which can include the synthesis of a precursor at the start and at least one calcination step at the end.…”