Ultrastable and High-Performance Silk Energy Harvesting Textiles

Abstract

• An energy harvesting textile with an elegant trade-off of mechanical and triboelectric performance was constructed by hierarchical structural design. • Modified rotor co-spinning technique was developed to produce triboelectric yarns in large scale. • Mass-producible energy harvesting textiles show ultrahigh stability withstands millions of multi-type cyclic deformations and various applications. ABSTRACT Energy harvesting textiles (EHTs) have attracted much attention in wearable electronics and the internet-of-things for real-time mechanical energy harvesting associated with human activities. However, to satisfy practical application requirements, especially the demand for long-term use, it is challenging to construct an energy harvesting textile with elegant trade-off between mechanical and triboelectric performance. In this study, an energy harvesting textile was constructed using natural silk inspired hierarchical structural designs combined with rational material screening; this design strategy provides multiscale opportunities to optimize the mechanical and triboelectric performance of the final textile system. The resulting EHTs with traditional advantages of textiles showed good mechanical properties (tensile strength of 237 ± 13 MPa and toughness of 4.5 ± 0.4 MJ m −3 for single yarns), high power output (3.5 mW m −2), and excellent structural stability (99% conductivity maintained after 2.3 million multi-type cyclic deformations without severe change in appearance), exhibiting broad application prospects in integrated intelligent clothing, energy harvesting, and human-interactive interfaces.

Towards Truly Wearable Systems: Optimizing and Scaling Up Wearable Triboelectric Nanogenerators

“…Incidentally, triboelectric series contains a large number of common textile polymers and materials ( Figure 2 B) ( Liu et al., 2018a , 2018b ), which facilities the use of existing textile materials for TENG applications ( Zou et al., 2019 ). For instance, textile substrates composed of dielectric polymers such as cotton ( Chen et al., 2018 ; Ning et al., 2018 ), silk ( Choi et al., 2017 ; He et al., 2020 ; Ye et al., 2020a ), nylon ( Gong et al., 2017 ), polyester ( Dong et al., 2017a ; Pu et al., 2016a ), polyethylene terephthalate (PET) ( Xiong et al., 2018 ; Zhang et al., 2016 ), polylactic acid ( Pan et al., 2018 ), polyurethane (PU) ( Kim et al., 2019 ), and carbon fibers ( Chen et al., 2018 ) have been used as wearable TENG contact surfaces. In some cases, additional triboelectric coatings using materials such as polytetrafluoroethylene (PTFE) ( Cheng et al., 2017 ; Ning et al., 2018 ), polydimethylsiloxane (PDMS) ( Dong et al., 2017a ; Lee et al., 2015 ), silicone rubber ( Pan et al., 2018 ), perylene ( Zhang et al., 2016 ), and polyvinylidene fluoride (PVDF) ( Guo et al., 2018 ), which are also associated with textiles, were used to enhance triboelectric performance.…”

“…Typically, such fabrications take place in the form of triboelectric modifications in yarn or fabric form. For instance, the fiber/yarn-based TENG fabrication methods include laboratory-scale electrospinning ( Li et al., 2020 ), wrapping or coiling with a motor ( Lou et al., 2020 ; Ye et al., 2020a ), twisting techniques ( Zhou et al., 2014a , 2014b ), etc. These yarns and fibers are typically embedded or converted into fabrics using sewing ( He et al., 2019 ; Lai et al., 2017 ), hand weaving ( Liu et al., 2019a , 2019b ; Zhang et al., 2016 ), shuttle weaving ( Chen et al., 2016 ), hand knitting ( Dong et al., 2017b ), pilot-scale nonwoven techniques ( Peng et al., 2019 ), and embroidery ( Sala de Medeiros et al., 2019 ) methods.…”

“…Considering their structure, fiber/yarn-related TENGs are divided into two sub-categories: core-shell and sandwiched structures. TENG developments at fiber/yarn stage allow for maximum control and modification capabilities of the energy generators ( Liu et al., 2019a , 2019b ; Ma et al., 2020 ; Ye et al., 2020a ; Yu et al., 2017 ); however, their handling and processing have been difficult due to small size and weak mechanical properties.…”

“…Core-shell fiber and yarn structures are popular for energy harvesting and self-powered sensing. Some of the core-shell TENGs operate in single-electrode mode in which the human skin acts as the counter-triboelectric surface ( Dong et al., 2018 , 2017b ; Park et al., 2017 ), whereas some reports indicate duel core-shell structures that contain two triboelectric layers and two electrodes ( Liu et al., 2019a , 2019b ; Tian et al., 2018 ; Ye et al., 2020b , 2020a ). Core-shell structure allows the core material to be protected within the surrounding sheath structure ( Cheng et al., 2017 ; He et al., 2017 ), with additional advantages such as ease of fabrication and ability to withstand mechanical stresses.…”

Violin String Inspired Core-Sheath Silk/Steel Yarns for Wearable Triboelectric Nanogenerator Applications

“…However, they are vulnerable to the environment, and are invalid when being sheltered during body movement. On the other hand, triboelectric nanogenerator (TENG) has attracted considerable attention in wearable electronics and the internet-of-things for harvesting mechanical energy associated with human activities [11][12][13]. Compared with conventional electromagnetic generators, TENGs feature advantages in lightweight, wide choice of materials and effectiveness in low-frequency energy harvesting [14].…”