Hydrophobic sponge structure-based triboelectric nanogenerators using an inverse opal structured film for sustainable energy harvesting over a wide range of humid atmosphere have been successfully demonstrated. The output voltage and current density reach a record value of 130 V and 0.10 mA cm(-2) , respectively, giving over 10-fold power enhancement, compared with the flat film-based triboelectric nanogenerator.

Highly stretchable 2D fabrics are prepared by weaving fibers for a fabric-structured triboelectric nanogenerator (FTENG). The fibers mainly consist of Al wires and polydimethylsiloxane (PDMS) tubes with a high-aspect-ratio nanotextured surface with vertically aligned nanowires. The fabrics were produced by interlacing the fibers, which was bonded to a waterproof fabric for all-weather use for fabric-structured triboelectric nanogenerator (FTENG). It showed a stable high-output voltage and current of 40 V and 210 μA, corresponding to an instantaneous power output of 4 mW. The FTENG also exhibits high robustness behavior even after 25% stretching, enough for use in smart clothing applications and other wearable electronics. For wearable applications, the nanogenerator was successfully demonstrated in applications of footstep-driven large-scale power mats during walking and power clothing attached to the elbow.

Despite the fast development of various energy harvesting and storage devices, their judicious integration into efficient, autonomous, and sustainable wearable systems has not been widely explored. Here, we introduce the concept and design principles of e-textile microgrids by demonstrating a multi-module bioenergy microgrid system. Unlike earlier hybrid wearable systems, the presented e-textile microgrid relies solely on human activity to work synergistically, harvesting biochemical and biomechanical energy using sweat-based biofuel cells and triboelectric generators, and regulating the harvested energy via supercapacitors for high-power output. Through energy budgeting, the e-textile system can efficiently power liquid crystal displays continuously or a sweat sensor-electrochromic display system in pulsed sessions, with half the booting time and triple the runtime in a 10-min exercise session. Implementing “compatible form factors, commensurate performance, and complementary functionality” design principles, the flexible, textile-based bioenergy microgrid offers attractive prospects for the design and operation of efficient, sustainable, and autonomous wearable systems.

Robust nanogenerator based on poly(tert-butyl acrylate)–grafted PVDF copolymers via dielectric constant control is demonstrated.

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The lack of compact integration, including fusing of skin-interfaced direct, rapid independent data visualization along with light, safe stretchable batteries, hinders progress towards the creation of fully autonomous comprehensive wearable monitoring platforms. Here we present a highly integrated epidermal sensing platform combining electrochemical sensors with stretchable battery and ultra-low power digital display that instantaneously visualizes the results via 10 individually addressable electrochromic pixels. The all-around stretchable patch can operate independently as a standalone device to directly display the concentration of various electrolytes or metabolites, freeing it from any wired or wireless connection to other equipment. Fabricated via high-throughput printing of customized elastomeric inks, the integrated system presents robust mechanical performance, enduring over 1500 stretching cycles without affecting its sensing and display capabilities. The fast-responding display exhibits stability over 10,000 ON/OFF cycles, and upon coupling with the high-performance stretchable battery, can serve 14,000 sensing sessions in a week-long usage. Merging ultra-low power consumption, independent operation, rapid data display and superior mechanical performance, this fully autonomous multifunctional self-sustainable wearable sensing platform is of high practicality and convenience for diverse practical applications in professional sports, personalized wellness management, and beyond. MainSoft electronics have gathered considerable attention over the past decade as attractive alternatives to their rigid bulky counterparts, for applications in on-body sensing and human-machine interfacing. [1][2][3][4] In particular, many integrated epidermal sensing systems have been developed as "labs-on-the-skin", capable of recording a myriad of mechanical, electrical, physiological, and electrochemical signals, towards applications in healthcare, wellness and tness. [5][6][7][8] The current development of wearable sensors has evolved from the study of physical and chemical sensors alone towards the integration of sensors with energy management, signal acquisition, and data interfacing electronics. 9-14 Due to the lack of high-performance wearable batteries, most wearable electronics currently operate with commercial lithium polymer pouches or coin cells, which are rigid, unsafe, and bottlenecks the product design.Avoiding such battery-related design limitations, conformal epidermal sensors were often designed with wired connections or short-range power delivery schemes, which in turn compromise the system autonomy and limit the user's mobility. 9,11,15−18 Furthermore, such integrated sensors rely on wireless data transmissions, which calls for the need for external devices (e.g., computers, mobile smartphones, customized receivers) for users to obtain the sensing results. 9,11,19−21 Such lack of direct access to sensing results has led to the inconvenience and impracticality of many existing wearable sensors in their rea...

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Inspired by traditional energy-autonomous microgrids, this perspective summarizes the key design and energy-budgeting considerations and outlook of integrated wearable systems.