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. This work is the first to use PVP-grafted interface modification and electrospinning to synthesize flexible free-standing anode for LIBs. PVP-grafted modifies the interface between SiO 2 nanoparticles and electrospinning solution to prevent SiO 2 nanoparticles from aggregation before and after electrospinning, and mesoporous is introduced into carbon nanofibers, which make the anode exhibit excellent cycling and lithium storage performance. [Display omitted] • Uniform and mesoporous SiO 2 @CNF is available by PVP-grafted interface modification. • PVP-g-SiO 2 @CNF exhibits smooth surface with uniformly embedded SiO 2 nanoparticles. • By means of thermal decomposition of PVP, mesoporous is introduced into CNF. • PVP-g-SiO 2 @CNF anode presents increased reversible capacity and cycle stability. [ABSTRACT FROM AUTHOR]