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

ᅟ: Ag-coated spherical Li₄Ti₅O₁₂ 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 Li₄Ti₅O₁₂. The electrochemical impedance spectroscopy (EIS) analyses demonstrated that the excellent electrical conductivity of the Li₄Ti₅O₁₂/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 Li₄Ti₅O₁₂ exhibited excellent electrochemical performance. Thus, with an appropriate silver content of 5 wt.%, the Li₄Ti₅O₁₂/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.

ISRCTN NARL-D-17-00568.