石墨烯在柔性锂离子电池中的应用及前景

Graphene for flexible lithium-ion batteries: Applications and prospects

随着具有变形功能的移动电子设备的出现和发展,为其供电的可变形、柔性锂离子电池近年来受到广泛关注.柔性锂离子电池一般指具有可逆弹性变形能力,同时可正常工作的锂离子电池.按照变形难易程度,大部分研究中的柔性锂离子电池,均指可弯折柔性锂离子电池.本文总结了石墨烯在可弯折柔性锂离子电池领域的进展情况.石墨烯具有很高的电子电导率,可将石墨烯附着于高分子、纸、纺织布等柔性基底上,利用基底提供柔性支撑、力学性能,石墨烯提供导电网络,形成石墨烯/柔性基体复合结构.利用石墨烯的二维柔性结构及表面官能团,与其他材料复合,能够制备出一体化石墨烯复合柔性电池电极.石墨烯柔性复合材料作为电极时,能够提高电池的整体能量密度,因此具有更广阔的发展前景.本文同时介绍了柔性锂离子电池的力学特性和电化学性能表征方法,并对柔性锂离子电池的未来发展方向进行了预测.柔性锂离子电池发展趋势是提高其变形能力,并赋予柔性锂离子电池一定的可拉伸性能,以使其适应各种复杂应用;新型柔性锂离子电池也将具有自修复和快速充电能力;未来同时将研究喷涂或打印等新型柔性电极的制备和器件优化设计.虽然仍然存在尚待解决的问题,石墨烯柔性锂离子电池经过适当的电化学性能和力学性能改进,将在移动电子领域得到广泛应用.

With the advent of flexible electronics, flexible lithium-ion batteries （LIBs） have attracted great attention as a promising power source in the emerging field of flexible and wearable electronic devices. Flexible LIBs are generally LIBs that can operate within the normal elastic range. When the external force is unloaded, it can completely restore its original state without any remaining plastic deformation. According to the different types of deformation, most of the as-reported flexible LIBs are referred to as bendable LIBs. This review summarizes the recent developments in the application of graphene in bendable LIBs. Graphene has superior electronic conductivity. Thus, graphene can act as a type of conductive phase to form composite films containing polymers, paper and cloth. In this structure, graphene has a conductive network and the substrates provide a flexible support. Because of its unique two dimensional structure and rich functional groups, graphene can form composites with other active materials. Graphene-based materials can work as flexible electrodes and can effectively improve the overall energy density of LIBs, making them highly anticipated in the near future. This review also introduces methods to characterize the mechanical and electrochemical properties of flexible LIBs. In this review, the trends of flexible LIBs are also included. Future flexible LIBs will be stretchable, enabling them to work under different conditions. Newly developed flexible LIBs should also have self-healing abilities and should be able to be charged at high rates. Although there are still many problems to overcome, the ubiquitous applications of flexible LIBs with superior electrochemical and mechanical properties in flexible electronic devices are highly anticipated in the near future.