Wearable thermoelectric devices show promises to generate electricity in a ubiquitous, unintermittent and noiseless way for on-body applications. Threedimensional thermoelectric textiles (TETs) outperform other types in smart textiles owing to their out-of-plane thermoelectric generation and good structural conformability with fabrics. Yet, there has been lack of efficient strategies in scalable manufacture of TETs for sustainably powering electronics. Here, we fabricate organic spacer fabric shaped TETs by knitting carbon nanotube yarn based segmented thermoelectric yarn in large scale. Combing finite element analysis with experimental evaluation, we elucidate that the fabric structure significantly influences the power generation. The optimally designed TET with good wearability and stability shows high output power density of 51.5 mW/m 2 and high specific power of 173.3 µW/(g·K) at ∆T= 47.5 K. The promising on-body applications of the TET in directly and continuously powering electronics for healthcare and environmental monitoring is fully demonstrated. This work will broaden the research vision and provide new routines for developing high-performance and large-scale TETs toward practical applications.

Hierarchically porous, micropore-domain graphene-based fiber-shaped supercapacitors show high energy density.

Graphene fiber-based supercapacitors (GFSCs) hold high power density, fast charge-discharge rate, ultralong cycling life, exceptional mechanical/electrical properties, and safe operation conditions, making them very promising to power small wearable electronics. However, the electrochemical performance is still limited by the severe stacking of graphene sheets, hydrophobicity of graphene fibers, and complex preparation process. In this work, we develop a facile but robust strategy to easily enhance electrochemical properties of all-solid-state GFSCs by simple plasma treatment. We find that 1 min plasma treatment under an ambient condition results in 33.1% enhancement of areal specific capacitance (36.25 mF/cm) in comparison to the as-prepared GFSC. The energy density reaches 0.80 μW h/cm in polyvinyl alcohol/HSO gel electrolyte and 18.12 μW h/cm in poly(vinylidene difluoride)/ethyl-3-methylimidazolium tetrafluoroborate electrolyte, which are 22 times of that of as-prepared ones. The plasma-treated GFSCs also exhibit ultrahigh rate capability (69.13% for 40 s plasma-treated ones) and superior cycle stability (96.14% capacitance retention after 20 000 cycles for 1 min plasma-treated ones). This plasma strategy can be extended to mass-manufacture high-performance carbonaceous fiber-based supercapacitors, such as graphene and carbon nanotube-based ones.

Fiber and/or yarn-shaped supercapacitors (FSSCs) have tremendous potential applications in portable and wearable electronics because of their light weight, good flexibility, and weavability. However, FSSCs usually show low energy density, which hinders their wide applications in wearable electronics. It remains challenging for the FSSCs to enhance their energy densities without sacrificing the flexibility and mechanical properties. Herein, we develop a chemical polymerization strategy to fabricate core–sheath porous polyaniline nanorods/graphene fibers which are used as the FSSCs electrode and show excellent electrochemical performances. The assembled polyaniline nanorods/graphene FSSCs exhibit an ultrahigh capacitance of 357.1 mF/cm2, a high energy density of 7.93 μWh/cm2 (5.7 mWh/cm3), and a power density of 0.23 mW/cm2 (167.7 mW/cm3). In addition, the FSSCs show ultralong cycling life (3.8% capacitance loss, 5000 charge–discharge tests), good rate capability (78.9% capacitance retention), and flexibility. The electrochemical performance of polyaniline nanorods/graphene FSSCs exceeds most reported hybrid FSSCs containing conducting polymers and/or metal oxide. This work may pave the way in structure design for portable and wearable energy storage devices.