Nanospace-controlled SnO2/Nanoporous Carbon Composite as a High-performance Anode for Sodium Ion Batteries

The electrochemical performance of SnO2 as an anode material for sodium ion batteries was greatly enhanced by embedding SnO2 nanocrystallites preferentially in the porous carbon. The appropriate loading of SnO2 (e.g., 62 wt %) so as to provide enough reaction space resulted in a high capacity retention of 84% in the 30th cycle and a high capacity of 387 mA h g−1. It was demonstrated by electrochemical impedance spectroscopy that the enhancement was due to lowering of the charge-transfer resistance in the nanospace-controlled composite.