The Recent Advance in Fiber‐Shaped Energy Storage Devices

Wearable electronic devices that can be directly worn on the human body or combined with daily textiles have experienced a booming development with the rapid development of mobile electronics. These wearable electronic devices strongly demand indispensable, high performance power systems with small size, high flexibility, and adaptability to comfort frequent deformations during usage. Fabricating high‐performance energy storage systems in a 1D shape like fiber is recognized as a promising strategy to address the above issues. These fiber‐shaped power systems with diameters from tens to hundreds of micrometers can adapt to various deformations for stable operation in close contact with the human body. It is also possible to further weave such 1D energy storage devices into breathable textiles with matching electrochemical performances for the wearable electronics. Here, the key advancements related to fiber‐shaped energy storage devices are reviewed, including the synthesis of materials, the design of structures, and the optimization of properties for the most explored energy storage devices, i.e., supercapacitors, aprotic lithium‐based batteries, as well as novel aqueous battery systems. The remaining challenges are finally discussed to highlight the future direction of the development of fiber‐shaped energy storage devices. The key contents related to fiber‐shaped energy storage devices, including the synthesis of materials, the design of structures, and the optimization of properties are discussed for the most explored energy storage devices, i.e., supercapacitors and batteries. Their integration with energy harvesting function in the 1D format is also highlighted. Finally, the remaining challenges of fiber‐shaped energy storage devices are summarized.