TiO2 embedded in ultrathin N-doping carbon nanosheets derived from shape-engineered titanium metal-organic frameworks for lithium-ion storage.

The utility of TiO 2 as an anode for lithium-ion storage is hindered by low conductivity and sluggish ionic diffusion. Here, the 2D N-doped carbon-wrapped TiO 2 (TiO 2 @NC) composite with a thickness of 5.5 nm derived from the 2D metal-organic framework was designed. This composite consisting of TiO 2 nanoparticles embedded in ultrathin N-doping carbon was used to address the rate and cyclability of Li-ion batteries. The 2D nanosheet morphology obtained from Ti 8 O 8 (OH) 4 (BDC-NH 2) 6 （NH 2 -MIL-125 (Ti)）effectively increases the specific surface area and shortens the electron/ion transport pathway. The chemical bond of Ti-C-O between TiO 2 nanocrystals and N-doping carbon further improve conductivity. Due to its unique structure, the produced TiO 2 @NC composite shows excellent cyclability with a reversible capacity of 110 mAh g–1 after 2000 cycles at 0.5 A g–1. Furthermore, the 2D TiO 2 @NC exhibits outstanding rate performance (71 mAh g–1 at 5 A g–1) compared to bulk TiO 2 @NC. This general concept can be extended to the development of metal oxide materials based on insertion mechanisms, such as Nb 2 O 5. • The 2D TiO 2 @N-doping carbon composite with a thickness of 5.5 nm is prepared. • Solvent-dependent variation of morphology NH 2 -MIL-125(Ti) MOF is investigated. • The TiO 2 nanocrystals embedded in ultrathin N-doping carbon nanosheets via chemical bonding. • The TiO 2 @N-doping carbon composite shows excellent lithium-ion storage performances. [ABSTRACT FROM AUTHOR]