Hollow Multi‐Shelled Structural TiO_2−x with Multiple Spatial Confinement for Long‐Life Lithium–Sulfur Batteries

Abstract

TiO2−x with well‐controlled hollow multi‐shelled structures (HoMSs) were designed and synthesized, via a sequential templating approach (STA), to act as sulfur carrier materials. They were explored as physico‐chemical encapsulation materials. Particularly, the sulfur cathode based on triple‐shelled TiO2−x HoMSs delivered a specific capacity of 903 mAh g−1 with a capacity retention of 79 % at 0.5 C and a Coulombic efficiency of 97.5 % over 1000 cycles. The outstanding electrochemical performance is attributed to better spatial confinement and integrated conductivity of the intact triple‐shell that combine the features of physico‐chemical adsorption, short charge transfer path along with mechanical strength.

Enhanced Chemisorption and Catalytic Effects toward Polysulfides by Modulating Hollow Nanoarchitectures for Long‐Life Lithium–Sulfur Batteries

“…The outer ImIP shell is adhered to inner CoS shell owing to the flexibility of ImIP. The double‐shelled structure is different from those reported with the gaps between the shells …”

“…To ascertain the nature of this chemisorption, the surface chemistry of Co‐NC@Co 9 S 8 /NPC after the adsorption experiment was examined by XPS analyses. In high‐resolution Co 2p XPS spectrum of Co‐NC@Co 9 S 8 /NPC‐Li 2 S 6 , the characteristic peaks of Co 0 , Co 2+ , and Co 3+ shift negatively to 778.0/793.0, 779.2/794.3, and 780.8/796.7 eV, respectively, when compared with those in pristine Co‐NC@Co 9 S 8 /NPC (Figures d and d), revealing strong chemical interaction between Co‐NC@Co 9 S 8 /NPC and the polysulfides . In the high‐resolution S 2p XPS spectra of Li 2 S 6 and Co‐NC@Co 9 S 8 /NPC‐Li 2 S 6 (Figure e), the binding energy peaks at 161.3 and 162.6 eV are assigned to terminal (S T –S T ) and bridging (S B –S B ,) sulfur species, respectively .…”

Revisiting the Role of Conductivity and Polarity of Host Materials for Long‐Life Lithium–Sulfur Battery

“…[ 28–30 ] In these cases, carbon is the main conductive host framework. Several metal oxides such as CuO, [ 31 ] SnO 2 , [ 32 ] Co 3 O 4 , [ 33 ] and TiO x [ 34 ] were found to be semiconductive and metallic due to their intrinsic defects and unique band structures, and they can therefore be used as sulfur hosts. For example, some nanostructured TiO x with different morphologies have been investigated as hosts in LSBs.…”

Recent advances of hollow-structured sulfur cathodes for lithium–sulfur batteries

“…4c-g). 70 To prepare TiO 2 HoMSs, carbonaceous microspheres (CMS) were firstly synthesized via the emulsion polymerization of sucrose through a hydrothermal process, followed by a controlled hydrolysis of TiCl 4 in the solution containing the as-obtained CMS solution, and a subsequent calcination step in air. The number of shells can be controlled via tuning the aging conditions and annealing process.…”