Encapsulating Tin Dioxide@Porous Carbon in Carbon Tubes: A Fiber-in-Tube Hierarchical Nanostructure for Superior Capacity and Long-Life Lithium Storage

A novel fiber-in-tube hierarchical nanostructure of SnO2@porous carbon in carbon tubes (SnO2@PC/CTs) is creatively designed and synthesized though a carbon coating on scalable electrospun hybrid nanofibers template and a post-etching technique. This 1D nanoarchitecture consists of double carbon-buffering matrixes, i.e., the external carbon tubular shell and the internal porous carbon skeleton, which can work synergistically to address the various issues of SnO2 nanoanode operation, such as pulverization, particle aggregation, and vulnerable electrical contacts between the SnO2 nanoparticles and the carbon conductors. Thus, the as-obtained SnO2@PC/CTs nanohybrids used as a lithium-ion-battery anode exhibits a higher reversible capacity of 1045 mA h g(-1) at 0.5 A g(-1) after 300 cycles as well as a high-rate cycling stability after 1000 cycles. The enhanced performance can be attributed to the wonderful merits of the external carbon protective shell for preserving the integrity of the overall electrode, and the internal porous carbon skeleton for inhibiting the aggregation and electrical isolation of the active particles during cycling.