3D Porous Carbon Encapsulated SnO₂ Nanocomposite for Ultrastable Sodium Ion Batteries

3D porous carbon encapsulated SnO₂ nanoparticles composite (SnO₂-PC) prepared by an efficient in situ methodology was applied as anode for sodium ion batteries (SIBs). It delivered a high reversible specific capacity of 280.1 mAh g⁻¹ after 250 cycles at a current density of 100 mA g⁻¹, with ultrahigh capacity retention of 91.63%. Notably, it can Exhibit 100 mAh g⁻¹ after 1000 cycles even at a high current density of 1600 mA g⁻¹. These greatly enhanced electrochemical properties of SnO₂-PC composite can be attributed to the superior structure that the electrical conductivity of the composite was improved by the porous carbon matrix, moreover, it can serve as a cushion during the process of Na ion insertion/extraction into the composite. Significantly, this kind of in situ synthesis method is portable for other similar composite.