Synthesis of Spherical Silver-coated Li4Ti5O12 Anode Material by a Sol-Gel-assisted Hydrothermal Method

Abstract

Ag-coated spherical Li 4 Ti 5 O 12 composite was successfully synthesized via a sol-gel-assisted hydrothermal method using an ethylene glycol and silver nitrate mixture as the precursor, and the influence of the Ag coating contents on the electrochemical properties of its was extensively investigated. X-ray diffraction (XRD) analysis indicated that the Ag coating does not change the spinel structure of Li 4 Ti 5 O 12 . The electrochemical impedance spectroscopy (EIS) analyses demonstrated that the excellent electrical conductivity of the Li 4 Ti 5 O 12 /Ag resulted from the presence of the highly conducting silver coating layer. Additionally, the nano-thick silver layer, which was uniformly coated on the particles, significantly improved this material's rate capability. As a consequence, the silver-coated micron-sized spherial Li 4 Ti 5 O 12 exhibited excellent electrochemical performance. Thus, with an appropriate silver content of 5 wt.%, the Li 4 Ti 5 O 12 /Ag delivered the highest capacity of 186.34 mAh g −1 at 0.5C, which is higher than that of other samples, and maintained 92.69% of its initial capacity at 5C after 100 cycles. Even at 10C after 100 cycles, it still had a capacity retention of 89.17%, demonstrating remarkable cycling stability. via a sol-gel-assisted hydrothermal method using ethylene glycol and a silver nitrate mixture as the precursor for the coating layer, which significantly improved the electronic conductivity and the electrochemical performance of Li 4 Ti 5 O 12 . 2. The spherical morphology could induce a large tap density and consequently enhance the volumetric energy density.

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

“…Many researchers have optimized the synthesis of LTO using hydrothermal processes combined with other techniques such as microwave [ 351 , 370 , 371 ], sol–gel [ 372 , 373 ], dispersion [ 367 ], and ball milling [ 374 ]. Ultrathin LTO nanosheets with ordered microstructures were prepared via a polyether-assisted hydrothermal process [ 212 ].…”

“…After 3 h, 3 mmol glycolic acid was added, and this solution was heated at 80 •C with stirring for 6 h to remove excess H2O2 and NH3 and form a gel-like orange precursor. The 20 mL aqueous solution containing the Ti precursor, 0.3 mol L −1 CTAB, and 0.5 mol L −1 LiOH was stirred for 1 h, and hydrothermally treated into a Teflon-lined stainless autoclave maintained at 180 °C Many researchers have optimized the synthesis of LTO using hydrothermal processes combined with other techniques such as microwave [351,370,371], sol-gel [372,373], dispersion [367], and ball milling [374]. Ultrathin LTO nanosheets with ordered microstructures were prepared via a polyether-assisted hydrothermal process [212].…”

“…Using the same synthesis process but prolonging the hydrothermal reaction time to 24 h, an urchin-like morphology was obtained (Figure 13). Many researchers have optimized the synthesis of LTO using hydrothermal processes combined with other techniques such as microwave [351,370,371], sol-gel [372,373], dispersion [367], and ball milling [374]. Ultrathin LTO nanosheets with ordered microstructures were prepared via a polyether-assisted hydrothermal process [212].…”

Strategic Design of Lithium-Rich Hierarchical Li1.2Mn0.54Ni0.13Co0.13O2 Microcubes as High-Capacity Cathodes for Lithium-Ion Batteries

“…These Li-rich manganese oxides are regarded as the next-generation cathode electrode for LIBs because of their high theoretical specific energy (900 Wh kg –1 ) and of delivering a high specific capacity of >240 mAh g –1 in a high-voltage window of 2.0–4.8 V. , Though they satisfy the high specific capacity requirement by combined cationic and anionic redox activities, their large-scale commercialization still faces basic obstacles. In general, issues associated with the Li-rich manganese oxides include large irreversible capacity loss during the initial cycle caused by the loss of oxygen from the activation of Li 2 MnO 3 compound in the surface lattice and voltage decay during cycling induced by the layered to spinel structure transformation, which ultimately generates harsh and capacity fading upon cycling due to cation mixing. − To overcome these problems, many approaches have been adopted for enhancing the structural stability and electrochemical performance of Li-rich manganese oxide cathode electrodes. Electrode modifications with metal oxides, aluminum fluoride, and phosphates , being regarded as a protective surface layer have been suggested as a potential way to extend the cycle life of Li-rich manganese cathode material.…”