PVP-grafted synthesis for uniform electrospinning silica@carbon nanofibers as flexible free-standing anode for Li-ion batteries

The application of the SiO 2 anodes for flexible and free-standing lithium-ion batteries (LIBs) is restricted by the weaknesses of SiO 2 nanoparticles , such as agglomeration, huge volume expansion and rapid capacity fading during charge/discharge cycles. Herein, the PVP-grafted-silica@carbon nanofibers (PVP-g-SiO 2 @CNF) flexible free-standing anode with high capacity and long cycle stability is successfully fabricated by PVP-grafted-SiO 2 , electrospinning and subsequent heat treatment . PVP modifies the interface between SiO 2 nanoparticles and electrospinning solution to prevent the nanoparticles from aggregation, which makes them are uniformly encapsulated in nanofibers. The uniform structure is beneficial to enhance the interface contact between SiO 2 and Li + , and alleviate volume expansion during lithiation . Furthermore, PVP introduces mesoporous into carbon nanofibers , facilitating the transports of ions and electrons to attain high-rate performance. As a flexible free-standing anode material for LIBs, PVP-g-SiO 2 @CNF achieves high reversible capacity, high-rate capacity and superior cycle stability (440 mAh g −1 at 0.1 A g −1 after 200 cycles), especially 89% capacity retention after 180° bending deformation . Consequently, enhanced capacity and cycle stability for flexible free-standing anode are available through PVP-grafted interface modification and electrospinning.