Copper‐Doped Dual Phase Li₄Ti₅O₁₂–TiO₂ Nanosheets as High‐Rate and Long Cycle Life Anodes for High‐Power Lithium‐Ion Batteries

Abstract

Cu-doped Li4 Ti5 O12 -TiO2 nanosheets were synthesized by a facile, cheap, and environmentally friendly solution-based method. These nanostructures were investigated as an anode material for lithium-ion batteries. Cu doping was found to enhance the electron conductivity of the materials, and the amount of Cu doped controlled the crystal structure and content of TiO2 . In addition, the samples, which benefit from multiphases and doping, exhibited much improved capacity, cycle performance, and high rate capability over Cu-free Li4 Ti5 O12 -TiO2 . The discharge capacity of the 0.05 Cu-doped sample was 190 mAh g(-1) at 1C, and even 144 mAh g(-1) was obtained at 30C after 100 cycles. Moreover, after 500 cycles at 30C, the discharge capacity remained at approximately 130 mAh g(-1) . The excellent electrochemical performance of the cell demonstrated that Cu-doping was able to adjust and control the Li4 Ti5 O12 -TiO2 system appropriately.

Fabrication of Li4Ti5O12-TiO2 Nanosheets with Structural Defects as High-Rate and Long-Life Anodes for Lithium-Ion Batteries

“…All these three peaks can be assigned to the three strongest peaks of anatase-TiO 2 22 . Meanwhile, the peaks of rutile-TiO 2 can be observed at 27.5 and 54.3° 24 . These observations confirm the existence of the TiO 2 phases (anatase and rutile), and a phase transition from anatase to rutile could start when the calcination temperature exceeds 400 °C.…”

“…However, it is inexplicable that the LTO-RT-AT with the highest content of oxygen vacancies has a relatively lower content of Ti 3+ in comparison with LTO-RT. Based on equilibrium of chemical valence, the content of oxygen vacancies is usually related to the content of Ti 3+ in titanium-based oxides 24 . Therefore, the likely reason is the existence of lithium vacancies in the LTO-RT-AT.…”

“…6c, including LTO-TiO 2 nanowire arrays 50 , copper-doped LTO-TiO 2 nanosheets 24 , rutile-TiO 2 coated LTO 23 , petal-like LTO-TiO 2 nanosheets 51 , amorphous carbon coated LTO-TiO 2 20 , hierarchical LTO-TiO 2 microsphere 52 , LTO/rutile-TiO 2 composite 53 and LTO-TiO 2 -C nanocrystallines 12 . It is clear that the LTO-RT-AT possesses ultrahigh capacities and remarkable rate capability at various rates.…”

Cr-Doped TiO2 Core–Shell Nanospheres with Enhanced Photocatalytic Activity and Lithium Storage Capacity

“…22 In addition, the voltage di®erence between the charge and discharge of Cr-TiO 2 is smaller than undoped TiO 2 , suggesting weaker polarization. 28 The cycling performance of Cr-TiO 2 is illustrated in Fig. 6(b), the Cr-TiO 2 exhibits better cycling performance than that of undoped TiO 2 .…”

Electrochemical performance of ZnO-coated Li 4 Ti 5 O 12 composite electrodes for lithium-ion batteries with the voltage ranging from 3 to 0.01 V

“…Surface coating [3–6], cation doping [7–10] and making composites [11–13] have been intensively studied and demonstrated to be three main methods to modify Li 4 Ti 5 O 12 powders effectively in the voltage range of 3–1 V. Most recently, it becomes more attractive with the greatly improved theoretical capacity (293 mAh g −1 ) in the extended voltage range of 3–0.01 V [14–16]. A small amount of research has been conducted to improve the electrochemical performance by cation doping [17–21] and making composites [22,23].…”