▎ 摘　　要

Flexible batteries are of great importance for the application in flexible electronic devices. In this paper, a flexible film electrode was designed and prepared by using three-dimensional graphene as a conductive network and polyimide (PI) as an active material. Structural characterization indicates the formation of a uniform composite of PI and graphene. The weight ratio of the active material in the film electrode reaches 80%, and no additive is required during the electrode preparation processes. Compared with the electrode prepared by a conventional method, the hierarchical structure of graphene composited PI in the proposed electrode results in lower resistance for the reaction with lithium ions. PI exhibits a specific capacitance of 175 mA h g(-1) as well as high rate performance. After 150 charge-discharge cycles at 0.5 C, 82% of the initial capacity was retained. This hierarchical graphene/PI film has high potential as a cathode for flexible lithium batteries.