Restacking-free crumpled anatase TiO2 nanosheets synthesized by spray pyrolysis for high-performance Na-ion battery anodes

Anatase TiO ₂ nanosheets have received considerable attention as high-power anodes for Na-ion batteries (SIBs) owing to their excellent electrochemical activities and ultrathin electron pathways in the out-of-plane direction. However, the large-scale synthesis of anatase TiO ₂ nanosheets remains challenging. Although the top-down approach of liquid-phase exfoliation is an established method for mass producing high-quality TiO ₂ nanosheets, it is difficult to prevent nanosheet restacking owing to electrostatic attraction that occurs during the conventional drying process. To overcome this inherent drawback, crumpled anatase TiO ₂ nanosheets were designed and synthesized without restacking and agglomeration by scalable spray pyrolysis, which effectively improved the rate performance of SIBs. Even without carbon coating, the anatase TiO ₂ nanosheet exhibited high reversible capacity (243.9 mA h g ^-1 at 0.1 mA g ^-1) and excellent long-term cycling stability (156.25 mA h g ^-1 after 10,000 cycles). Therefore, the developed synthesis strategy is suitable for the practical, large-scale production of nanosheets, which are promising anode materials for high-performance SIBs.