Structural Modification and Deformable Design of Electrospun Sn@C Nanofiber Anodes Through Oxide Doping for Flexible Lithium‐Ion Batteries

ABSTRACT Size‐controllable Sn nanoparticles are designed in this work via oxide doping to be uniformly embedded into flexible N‐doped carbon nanofibers, in which the agglomeration and migration of Sn are effectively restrained due to the suppressive effect of selected oxides, including SiO 2 , TiO 2 , and ZnO. Benefiting from unique merits of the embedment structure, such as ultrahigh aspect ratio, superior adhesion, and ideal stability, the flexible freestanding and highly robust electrode (Sn/TiO 2 @C, STC) is fabricated and exhibits a reversible specific capacity of 968.4 mAh g −1 after 100 cycles at 0.1 A g −1 . Moreover, the STC electrode contributes to a cycle lifespan of over 1000 cycles with a high specific capacity of 519.7 mAh g −1 at 1.0 A g −1 and a capacity decay as low as 0.00185% per cycle. Remarkably, practical application potential of the STC electrode was demonstrated by being assembled into a pouch cell, which not only works stably under bending states but also presents a specific capacity of 954.8 mAh g −1 after 150 cycles at 0.1 A g −1 . This composite fiber anode avoids extra use of polymer binder, current collector, and conductive additive, and exhibits a great potential in the practical application of flexible energy storage devices.