Flexible/foldable energy storage devices with high gravimetric energy density are highly desired due to the development of wearable electronic equipment. In this work, highly flexible/foldable MnO-based lithium-ion battery anode composed of MnO nanoparticles encapsulated in carbon nanofibers (MnO nanoparticles@CNFs) are fabricated by hydrothermal, electrospinning and subsequently thermal treatment. The freestanding, foldable carbon nanofibers membrane with sufficient void space in carbon nanofibers and containing over 50 wt % of MnO can be directly used as a freestanding anode for LIBs. This hybrid membrane electrode exhibites remarkable reversible capacity (773 mA h g-1 at 0.2 A g−1 after 100 cycles). It also shows outstanding rate capability (407 mA h g-1 at 2 A g−1) and robust long cycling stability with specific capacity (400 mA h g-1 at 1 A g−1 after 500 cycles). This work proposes a simple, low-cost and environmental friendly method for preparing free-standing and binder-free composite membrane electrodes with sufficient buffer space, high loading and remarkable electrochemical properties used in lithium ion batteries.