Flexible organic cathodes with 3,4,9,10-perylenetetracarboxylic diimide (PDI) as the active component, carbon black (CB) as the conductive agent and thermoplastic polyurethane (TPU) as the elastomeric matrix are obtained in this work via a solution-based phase inversion approach. In the resulting PDI/CB/TPU cathodes, the mass ratios of the three components manifest profound influences on their composition, flexibility, conductivity and lithium storage behavior. The integrated PDI/CB/TPU cathode with optimized ratio can deliver impressive rate capability and good cycling stability in lithium ion batteries (LIBs). More importantly, the full LIBs with PDI/CB/TPU cathode and carbon cloth anode exhibit excellent electrochemical performances, which show no decay even at bending states, demonstrating the appealing prospects of the solution-processed organic cathodes in wearable secondary batteries.