Monolayer Sodium Titanate Nanobelts as a Highly Efficient Anode Material for Sodium-Ion Batteries

Monolayer atomic crystals show significant advantages in improving charge storage kinetics for electrode materials. While notable progress is made, challenges remain in producing nanocrystals with desirable configurations, dimensions, and crystallographic properties. Here, 1D single-crystal nanobelts assembled from monolayer sodium titanate nanobelts are reported with highly exposed active sites as anode materials for sodium-ion batteries (SIBs). The unique structural properties of the 1D single-crystal nanobelts offer excellent electrochemical activity, electrochemo-mechanical stability, and well-maintained structural integrity, leading to highly efficient sodium ion storage performance. Insights into the electrochemical reaction processes, as revealed by in situ transmission electron microscopy, in situ synchrotron X-ray diffraction, and theoretical calculations, indicate that the 1D single-crystal nanobelts enable favorable sodium ion storage kinetics and a low-strain characteristic. This facilitates fast charge/discharge capability and long-term cycling stability for up to 5000 cycles at 20 C. Moreover, the 1D single-crystal nanobelts demonstrate practical applicability. A pouch cell assembled with the 1D single-crystal nanobelts anode and iron-based Prussian blue cathode exhibits highly stable cycling, achieving a low capacity fading ratio of ≈0.05% per cycle over 150 cycles. This study provides an innovative design principle to enhance the charge storage capability of electrode materials through intelligent structural nanoengineering.