High Reversible Pseudocapacity in Mesoporous Yolk–Shell Anatase TiO₂/TiO₂(B) Microspheres Used as Anodes for Li‐Ion Batteries

Abstract

As an anode material for lithium-ion batteries, titanium dioxide (TiO 2 ) shows good gravimetric performance (336 mAh g −1 for LiTiO 2 ) and excellent cyclability. To address the poor rate behavior, slow lithium-ion (Li + ) diffusion, and high irreversible capacity decay, TiO 2 nanomaterials with tuned phase compositions and morphologies are being investigated. Here, a promising material is prepared that comprises a mesoporous "yolk-shell" spherical morphology in which the core is anatase TiO 2 and the shell is TiO 2 (B). The preparation employs a NaCl-assisted solvothermal process and the electrochemical results indicate that the mesoporous yolk-shell microspheres have high specific reversible capacity at moderate current (330.0 mAh g −1 at C/5), excellent rate performance (181.8 mAh g −1 at 40C), and impressive cyclability (98% capacity retention after 500 cycles). The superior properties are attributed to the TiO 2 (B) nanosheet shell, which provides additional active area to stabilize the pseudocapacity. In addition, the open mesoporous morphology improves diffusion of electrolyte throughout the electrode, thereby contributing directly to greatly improved rate capacity.

Enhanced Ionic/Electronic Transport in Nano‐TiO2/Sheared CNT Composite Electrode for Na+ Insertion‐based Hybrid Ion‐Capacitors

“…The synthesis of the SCNT framework and growth of TiO 2 nanoparticles is shown schematically in Figure a. It is typically seen that the hydrolysis of TTIP under hydrothermal conditions results in the growth of large spherical TiO 2 particles . However, in the current work, the SCNT framework inhibits the growth of large TiO 2 particles by providing many competing energetically favorable nucleation sites as well as through steric confinement of the particles within the framework.…”

Ti‐Based Oxide Anode Materials for Advanced Electrochemical Energy Storage: Lithium/Sodium Ion Batteries and Hybrid Pseudocapacitors

“…The unique nanoarchitecture ensured high specific capacity and excellent rate capability, delivering the best lithium storage performances among TiO 2 nanowire arrays anodes reported. Based on that, mesoporous yolk–shell anatase TiO 2 /TiO 2 ‐B microspheres consist of anatase TiO 2 as the core and TiO 2 ‐B as the shell, prepared by Caruso's group, exhibited high specific reversible capacity of 330 mA h g −1 at 0.2 C, and outstanding rate capability of 182 mA h g −1 at 40 C. The superior properties can be attributed to the additional active area to stabilize the pseudocapacity arising from the TiO 2 ‐B nanosheet shell.…”

Recent progress in Ti-based nanocomposite anodes for lithium ion batteries

“…Due to the tiny nanocrystals in the nanoshells, these TiO 2 nanoachitectures illustrated improved rate capacity and cycling stability. Wei et al [27] prepared a mesoporous yolk-shell spherical nanostructures composed of anatase TiO 2 (as a core) and TiO 2 (B) (as a shell), which demonstrated outstanding high-rate capability of 181.8 mAh/g at 40 C and excellent cycling stability for 500 cycles with only 0.004% capacity loss per cycle ( Fig. 2(g)).…”