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 SnO2 fibers (SnO2 fibers/rGO composite) was fabricated through electrospinning assisted by pyrolysis. The special core shell structure showed that porous SnO2 fibers as the "core" were completely protected by multilayer rGO as the "shell." Lithiation of SnO2 occurred through Li diffusion through the rGO wrapped into the SnO2 fibers, and natural void space facilitated SnO2 expansion upon lithiation. This unique structure effectively prevented the aggregation and pulverization of SnO2 fibers during lithiation and delithiation. The SnO2 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.