Efficient Na-Ion Storage in 2D TiS 2 Formed by a Vapor Phase Anion-Exchange Process

Hierarchical nanocomposites that couple downsized 2D materials with carbonaceous functional supports are promising electrode materials for metal ion batteries. Herein, a honeycomb-like Na-ion battery (NIB) anode material, which comprises 2D downsized TiS2 nanocrystals uniformly dispersed in a 3D porous carbon honeycomb, is developed by a vapor phase anion-exchange reaction of CS2 with a dual-template of TiO2 sealing in hydrogen-substituted graphdiyne (HsGDY). On the one hand, the 2D downsized TiS2 nanolayers offer much more accessible active sites for both Na+ storage and polysulfide trapping; on the other hand, the 3D porous hollow carbon nanoscale honeycomb not only provides numerous space-confined nanorooms to reduce the stacking of the tiny 2D TiS2 nanolayers and suppress the dissolution of polysulfide, but also works as built-in 3D conductive networks to support the electron/ion transfer and buffer the volume expansion during cycling. In light of this, such a hybrid 3D TiS2@carbon honeycomb achieves a high reversible capacity with high-rate and long-life performance for NIBs.