LAUSR

With the rapid advances in safe, flexible, and even stretchable electronic products, it is important to develop matching energy storage devices to more effectively power them. However, the use of conventional liquid electrolytes produces volatilization and leakage that are dangerous and requires strict packaging layers that are typically rigid. To this end, solid electrolytes that can overcome these problems have attracted increasing attention in recent decades. In this review article, three main types of solid electrolytes (i.e., inorganic, polymer, and composite electrolytes) are first described and compared in terms of their structures and properties. The advantages of solid electrolytes to make safe, flexible, stretchable, wearable, and self‐healing energy storage devices, including supercapacitors and batteries, are then discussed. The remaining challenges and possible directions are finally summarized to highlight future development in this field.