Realizing ultra-stable SnO2 anodes via in-situ formed confined space for volume expansion

Tin dioxide (SnO 2 ) is a promising anode material for lithium-ion and sodium-ion batteries. However, the huge volume expansion during cycling makes it far away from practical application. Herein, we report a template-free “heterogeneous carbonization” strategy for fabricating SnO 2 /carbon/void/carbon nanofibers (SCVC) compound membrane with finite spatial domain in carbon matrix as buffer layer for volume changes of SnO 2 . Reduced graphene oxide (rGO) is also imported into the SCVC membrane, acting as conductive binders to construct a free-standing SCVC-rGO electrode with exceptionally conductive network. The resultant SCVC-rGO anodes in lithium/sodium-ion batteries could deliver excellent electrochemical performances of higher reversible capacity, longer lifespan and superior rate capability. As lithium-ion battery anode, the SCVC-rGO electrode shows specific capacities of 950 mA h g −1 after 400 cycles at a current of 0.5 A g −1 , and 824 mA h g −1 after 650 cycles at 1 A g −1 . In sodium-ion batteries, the SCVC-rGO electrode gives rise to the specific capacity of 407 mA h g −1 after 2000 cycles at the current of 1 A g −1 with exceptional capacity retention.