Flexible energy storage devices are gaining considerable attentions due to their great potentials in the emerging flexible electronics market, ranging from roll-up displays, bendable mobile phones, conformable health-monitoring skin sensors to implantable medical devices. The development of reliable and flexible electrodes with low cost, high performance, superior stability and safety remains a great challenge to meet the requirements for many practical applications. On the other hand, structural design can also enhance their flexibility and electrochemical performance. On account of the low cost and easily accessible sodium resources, in the present review we mainly focus on recent progress in flexible energy storage devices with sodium-ions as the charge carriers. We begin with a brief introduction of flexible energy storage systems and the current development of flexible sodium-ion based energy storage devices. Then, a more detailed overview of recent progress on pliable materials in flexible sodium-ion batteries (SIBs) is presented, including carbon-based substrates materials (e.g., graphene, carbon cloths, carbon nanofibers (CNFs) and carbon nanotubes (CNTs)), metal-based materials (e.g., stainless steel, copper (Cu) and titanium (Ti) foils), other flexible substrate materials and electrolytes. This is followed by detailed discussion of the advancements in other flexible analogous sodium-based energy systems, such as the fiber-shaped flexible SIBs, sodium-ion capacitors (SICs), Na-S batteries and Na-Se batteries. Finally, future prospects and challenges are examined and possible solutions are brought up to inspire the future flexible sodium-based energy storage devices.

柔性能量存储设备由于在新兴的柔性电子市场中的巨大潜力而​​受到了广泛的关注，从卷式显示器，可弯曲的手机，舒适的健康监测皮肤传感器到可植入的医疗设备，应有尽有。为了满足许多实际应用的要求，开发具有低成本，高性能，优异的稳定性和安全性的可靠且柔性的电极仍然是巨大的挑战。另一方面，结构设计也可以增强其灵活性和电化学性能。由于低成本和易于获取的钠资源，在本综述中，我们主要关注以钠离子为电荷载体的柔性储能装置的最新进展。我们首先简要介绍一下柔性储能系统和基于钠离子的柔性储能设备的最新发展。然后，将详细介绍挠性钠离子电池（SIB）中柔韧性材料的最新进展，包括碳基基材材料（例如，石墨烯，碳布，碳纳米纤维（CNF）和碳纳米管（CNT）），金属基材料（例如不锈钢，铜（Cu）和钛（Ti）箔），其他柔性基板材料和电解质。接下来是对其他类似的挠性钠基柔性能源系统的进展的详细讨论，例如纤维状挠性SIB，钠离子电容器（SIC），Na-S电池和Na-Se电池。最后，研究了未来的前景和挑战，并提出了可能的解决方案，以激发未来的柔性钠基储能设备。