Flexible current collector–free LiFePO4/carbon composite film for high-performance lithium-ion batteries

A facile formation of free-standing LiFePO4/carbon (LiFePO4/C) composite film with flexibility and current collector–free is presented. This composite film has been prepared via a simple coating process by spreading out slurry onto a hydrophobic surface. Such free-standing film exhibits excellent flexibility and mechanical strength. The mechanical measurements show that the fracture strength and modulus of flexible film are up to 0.65 MPa and 109.6 MPa, respectively. The electrochemical properties of this film have been obtained in a half-cell configuration. The results display that the film delivers an initial discharge capacity of ~ 156 mAh/g at 0.1 C; the charge-discharge efficiency is as high as 98%. Moreover, at 10 C, the specific capacity can be kept at ~ 133 mAh/g, with very little capacity loss after 500 cycles (< 0.02‰ per cycle). The as-prepared flexible film is inexpensive and simple, providing a great potential for the commercialization of high-performance flexible lithium-ion batteries.