An Overview of Flexible Electrode Materials/Substrates for Flexible Electrochemical Energy Storage/Conversion Devices

Abstract The rise of portable and wearable electronics has largely stimulated the development of flexible energy storage and conversion devices. As one of the essential parts, the electrode plays critical role in determining the device performance, which required to be highly flexible, light‐weight, and conformable for flexible and wearable applications. However, it remains a formidable challenge in the design of appropriate flexible electrodes. Thus, considerable effort has been making to develop various flexible materials/substrates to fabricate flexible energy devices. Here, this review aims to provide a comprehensive survey on the recently developed free‐standing and flexible electrode materials/substrates for flexible electrochemical energy storage devices, which are categorized into four different types including metal‐based, carbon‐based, polymer‐based, and micro‐patterned flexible electrodes. The specific characteristics, fabrication methods, properties, and pros and cons of each type of materials are thoroughly analysed. Furthermore, challenges and future directions for designing flexible electrode materials are also discussed.