Flexible lithium-ion batteries (LIBs) are of increasing interest as mobile power supply for the next-generation of flexible electronics. The current flexible LIBs are generally limited by relatively poor ductility, short cycle-life and low charge and discharge rate. Herein, we report a rational design and preparation of flexible ultra-long, aligned carbon nanofibers thin films with embedded In2O3 nanocrystals (In2O3@FUACNFF) as a binder free anode for highly flexible LIBs. In this work, needleless electrospinning has been demonstrated to be to an effective method for the preparation of In2O3@FUACNFF with super-high throughput. The In2O3@FUACNFF can ensure excellent charge transport, electrolyte transport and mechanical flexibility, thus leading to excellent electrochemical performance and exceptional flexibility. The In2O3@FUACNFF exhibited excellent cycling ability even after 500 cycles, with a capacity of 545.6mAhg−1 at a current density of 200mAg−1 and rate performance even at the highest current density of 100Ag−1 with a reversible capacity of 224.2mAhg−1. Moreover, highly flexible full batteries were also fabricated to demonstrate the superior durability (the electrical stability of the manufactured flexible full battery was hardly affected after more than 120 times folding cycles), excellent cycle-ability (the capacity retention was almost 100% in the measured range from the 17th cycle on) and high rate performance (321.4mAhg−1 at a current density of 1000mAg−1).