A review of cathode modification based on carbon materials in flexible batteries

As a kind of battery that can work normally under deformation, flexible batteries are widely applied in wearable, portable and biomedical devices. However, the development and large-scale production of flexible batteries are restricted with the balance between the flexibility requirements and conductivity of the cathode. Modifying carbon-based materials used in cathodes is an effective means to address the poor electrochemical performance of flexible batteries. In this review, an extensive generalization about the preparation methods of cathode based on carbon materials including doping conductive materials, surface structure treatment, electrode macro-structure control, regulation of chemical properties, multilayer composite and treatment of carbon-based material precursors is enumerated. In addition, the modification of carbon-based materials in different types of batteries (zinc battery, lithium battery, supercapacitor, sodium battery and others) and batteries with different structures (1D, 2D and 3D) has been analyzed in detail. Finally, we have summarized the outlook section to provide some insights into the future prospects of cathode materials in flexible batteries. These discussions will offer more directions for the practical application of flexible batteries with superior electrochemical performance. • Various preparation methods of carbon-based materials for flexible batteries are outlined. • A generalization of carbon-based materials in different flexible batteries are reviewed. • An introduction of mechanism of carbon-based materials in flexible batteries are generalized. • Views are summarized for the future research in carbon-based materials for flexible batteries.