The emerging wearable and foldable electronic devices drive the development of flexible lithium ion batteries (LIBs). Carbon materials are considered as one of the most promising electrode materials for LIBs due to their light weight, low cost and good structural stability against repeated deformations. However, the specific capacity, rate capability and long-term cycling performance still need to be improved for their applications in next-generation LIBs. Herein, we report a facile approach for immobilizing phosphorus into a large-area carbon nanosheets/nanofibers interwoven free-standing paper for LIBs. As an anode material for LIBs, it shows high reversible capacity of 1100 mAh g−1 at a current density of 200 mA g−1, excellent rate capabilities (e.g., 200 mAh g−1 at 20,000 mA g−1). Even at a high current density of 1000 mA g−1, it still maintains a superior specific capacity of 607 mAh g−1 without obvious decay.