Self-limiting electrode with double-carbon layers as walls for efficient sodium storage performance
As a promising energy storage device, sodium ion batteries (SIBs) have attracted more and more attention. Nevertheless, the radius of sodium ion is much larger than that of lithium ion, it is still a significant challenge to solve the problem of volume expansion. To address the problem, here, a rational nanostructure consisting of CNTs as carbon matrix, and were sequentially coated with mesoporous SnO2 and N-doped porous carbon tube (NCT). The mesoporous SnO2 can alleviate the volume expansion caused by charge and discharge, and the N-doped porous carbon layer can further inhibit the volume expansion of SnO2. When used as an anode material in sodium ion batteries, the CNT@SnO2@NCT heterostructure achieve efficient capability (350 and 150 mA h g-1 at current densities of 0.1 and 2 A g-1, respectively).