Porous Core-Shell SnO2 fibers/rGO Composite and Its Lithium Storage Performance

In this work, a porous core–shell composite composed of reduced graphene oxide (rGO)-wrapped SnO 2 fibers (SnO 2 fibers/rGO composite) was fabricated through electrospinning assisted by pyrolysis. The special core–shell structure showed that porous SnO 2 fibers as the “core” were completely protected by multilayer rGO as the “shell.” Lithiation of SnO 2 occurred through Li diffusion through the rGO wrapped into the SnO 2 fibers, and natural void space facilitated SnO 2 expansion upon lithiation. This unique structure effectively prevented the aggregation and pulverization of SnO 2 fibers during lithiation and delithiation. The SnO 2 fibers/rGO composite electrode presented a super-high discharge capacity of 2,141 mAh g -1 at a current density of 0.4 A g -1 , 1,858 mAh g -1 at 0.8 A g -1 , 1,520 mAh g -1 at 1.6 A g -1 , and 874 mAh g -1 at 2.0 A g -1 after 10 cycles. The electrode showed a discharge capacity of 658 mAh g -1 at a current density of 4 A g -1 after 1,000 cycles.