Carbonized cotton fibers (CCFs) were prepared by the carbonization of commercial cottons at 700, 800 and 900 degrees C. The following characterizations indicated that the properties of the obtained CCFs could be effectively tuned by the carbonization temperatures. Containing both high conductivity and high aspect ratio, the CCFs could be used as the conductive agents for the construction of the integrated organic cathodes in lithium ion batteries (LIBs). With the optimized ratio of CCF from 900 degrees C, the organic LIB cathodes showed a high specific capacity of 135 mA h g(-1) at a current density of 0.05 A g(-1) and an impressive cyclizing stability by keeping 90.5% of the highest capacity value after 500 cycles at 0.5 A g(-1). The moderate mechanical stability of the CCF supported organic cathode enabled the further fabrication of flexible LIBs, which manifested stable performances at various bent states, confirming the potentials of CCFs in flexible energy storage devices. (c) 2020 Elsevier Inc. All rights reserved.