generators) have unveiled their enormous potential in the growth of wearable applications for healthcare, communication, fashion technology, energy harvest, and so on. [1][2][3][4][5][6][7] That has received great attention from the scientific and engineering community to develop electronic textiles (e-textiles) and wearable electronics in recent years. However, there are many general challenges for the commercialization and further growth of wearable electronics. [8][9][10] The major weakness of portable wearable electronic systems is the lack of stretchable and high-performance energy storage that is required to ensure the sustainable operation of the systems while mounted on moving surfaces (of humans and other beings). Here, conventional energy storage devices failed to address the usability in this wearable field due to their rigid and bulky nature. Besides, given hygiene issues, washability is one of the most desired features for the wearable electronic systems incorporated directly into fabrics. [11][12][13][14][15][16] Therefore, there exists a strong need for the development of reliable wearable energy devices which carry not only satisfactory energy storage and power delivery capabilities but also other robust features, such as stretchability and even washability, for integration with e-textiles.It is not denied that among the various energy storage devices, supercapacitors are gaining attraction for wearable electronics, mainly because of their salient properties such as excellent lifetime, fast charging/discharging rate, high power density, and lightweight for integration into portable electronic systems. [16][17][18][19][20] In recent years, research efforts have been devoted to the innovation of existing active materials, the design of new ones for wearable supercapacitors, and the establishment or enhancement of their merits by multifunctionalities, which can be adaptive to various purposes of uses in practice or commercialization. [21,22] Due to the versatile operation ability under multiple mechanical deformations (e.g., stretching, bending/ folding, and twisting), the stretchable platforms of supercapacitors have received further attention. [23][24][25][26][27][28] However, that has yet reached the ultimate goals for wearable energy devices in realworld applications, which demand not only stretchability but also more functionalities. [21,22,29] Thus, the development and innovation of textile-based supercapacitors, having stretchabilityThe attraction of electronic textiles for next-generation wearable electronic devices has raised the demands of washable and stretchable energy storage. However, negative effects of washing on the textile-based devices are majorly known. In this work, besides the innovation of a conventional stretchable composite based on carbon nanotubes (CNT) and polydimethylsiloxane (PDMS) for textile-based supercapacitors, findings regarding negative and positive effects of washing are introduced. Since the CNT-and-PDMS-based composite (CNT+PDMS) owns high stretchability but lo...