Silicon (Si) is expected to be a high-energy anode for the next generation of lithium-ion batteries (LIBs). However, the large volume change along with the severe capacity degradation during the cycling process is still a barrier for its practical application. Herein, we successfully construct flexible silicon/carbon nanofibers with a core–shell structure via a facile coaxial electrospinning technique. The resultant Si@C nanofibers (Si@C NFs) are composed of a hard carbon shell and the Si-embedded amorphous carbon core framework demonstrates an initial reversible capacity of 1162.8 mAh g−1 at 0.1 A g−1 with a retained capacity of 762.0 mAh g−1 after 100 cycles. In addition, flexible LIBs assembled with Si@C NFs were hardly impacted under an extreme bending state, illustrating excellent electrochemical performance. The impressive performances are attributed to the high electric conductivity and structural stability of the porous carbon fibers with a hierarchical porous structure, indicating that the novel Si@C NFs fabricated using this electrospinning technique have great potential for advanced flexible energy storage.
For the first time, we demonstrate a novel pan-milling mechanochemical technique for preparation of N-doped graphene nanosheets (NGNS) by utilizing solid-state shear-milling (S 3 M) graphite with melamine. It is found that S 3 M not only facilitates the direct exfoliation of graphite into few-layer graphene nanosheets (GNS), but also enables nitrogen element to be doped into the graphene using melamine as solid-state doping and assist-grinding agents. The prepared NGNS reveals a nitrogen doping content about 5.09 wt.%, and exhibits high reversible specific capacities about 582 mAh g −1 and 300 mAh g −1 at current densities of 100 mA g −1 and as high as 2 A g −1 , respectively, which are far superior to the commercial graphite as well as the undoped milled analogue when used as anode materials in lithium ion batteries (LIBs). The method presented in this article may provide a facial, low-cost, scalable and eco-friendly strategy for preparation of functional graphene as promising anode materials for high performance LIBs.
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