碳基柔性电极的结构设计, 制备和组装

Flexible electronics as an innovative technology to bring huge changes in people's daily lives have greatly stimulated the research and development of flexible energy storage devices. Among them, flexible lithium ion batteries (LIBs) are attracting remarkable interests due to their significant advantages. Flexibility of electrode has an important role on the electrochemical performance and stability of flexible LIBs. It requires that active particles can keep tightly in touch with their flexible substrate during the whole charge/discharge process, even though the batteries are bended, rolled, stretched or compressed. Carbon materials, such as carbon nanotubes, carbon fibers, graphene, carbon cloth, carbon paper and so on, as free-standing substrates are very popular owe to their deformability, excellent thermal and chemical stability, high conductivity and a wide potential window. In order to overcome the fundamental mismatch in mechanics and form between "rigid" active materials and "flexible" substrate, it is necessary to design the structure of composite electrode, increase the bonding strength and develop the novel fabrication route. Here, we review the progress and synthesis strategies of flexible electrodes based on carbon materials. It is described the effect of structure characteristic on electrochemical performance. According to this review, the self-standing flexible electrodes composed of active materials and carbon materials are commonly 3D porous network structures with various forms, such as sandwich structure. Currently, in-situ growth is standing out from the abundant synthesis methods because the bonding strength between active materials and carbon substrates can be obviously increased. Several typical prototypes and electrochemical performance of flexible LIBs are discussed briefly. The facing challenge and some perspectives of flexible electrodes in the future are also concluded. It can be sure that the advance in flexible electrodes with the combination of softness and hardness can promote the development of not only lithium-ion batteries, but also other energy storage devices.