Cobweb-Inspired Quintuple Network Structures toward High-Performance Wearable Electrochromic Devices with Excellent Bending Resistance

Abstract

Flexible electrochromic devices (FECDs) have been regarded as an ideal stratagem for wearable displays. However, it remains a great challenge to achieve long-term stability for high-performance FECDs due to their severe electrolyte deformation/leakage under repeated bending. Herein, inspired by the rough and fluffy microstructure of cobwebs, we prepared a porous polylactic acid (PLA) network through electrospinning and nonsolvent-induced phase separation. This loosely interlaced PLA network can be well infiltrated by electrolytes and exhibits extraordinarily high transparency; in addition, its surface contains numerous tiny holes to effectively load electrolytes to mitigate deformation. Furthermore, we also introduced silver nanowires (AgNWs) as the supporting network to load and connect electrochromic materials. After assembling them with graphene (GR) electrodes, a wearable FECD with a quintuple network structure (two GR networks, two AgNW networks, and one PLA network) was successfully prepared. The resulting FECD can realize high optical modulation (more than 70%), excellent cyclic stability (retain 95% after 1000 cycles), and innovative bending resistance (retain 84.8% after 6000 bending cycles). This work not only solves the long-lasting challenge of developing FECD with high optical modulation and bending resistances but also provides an energetic paradigm for diverse soft electronics used in harsh environments.

Progress in the Preparation and Application of Breathable Membranes

“…Electrospinning [ 59 , 60 , 61 ] utilizes electrostatic forces to draw a solution or melt, such as a polymer, from a tip or nozzle, creating a nanofiber film characterized by a high specific surface area and high porosity [ 62 ]. As a technique for generating nanofiber films, electrospinning offers lightweight material, small pore sizes, high porosity, and a customizable pore structure, which are ideal for creating a range of high-performance waterproof and breathable membranes [ 28 , 63 ].…”

Recent advances in nanofiber-based flexible transparent electrodes

“…This resolves the issue of liquid leakage to some extent without sacrificing the high ionic conductivity of ILs. Inspired by spider webs, Peng et al fabricated a wearable flexible electrochromic device with a five-layer structure using porous polylactic acid (PLA) NF webs, silver NFs, and graphene electrodes (figures 17(h)-(j)) [207]. As shown in figures 17(k)-(n), it achieves high light modulation over 70%, good bending performance (84.8% retention following 6000 cycles) and cyclic stability (95% retention following 1000 cycles).…”

Highly integrated all-in-one electrochromic fabrics for unmanned environmental adaptive camouflage

“…[8][9][10] Integrating electrochromic technology could endow conventional fabrics with some intelligent features beyond the primary functions of protection and fashion. [11][12][13][14][15][16] For instance, beneting from the tunability of multicolor or infrared characteristic, smart electrochromic fabrics (ECFs) have the potential to be applied as chameleonic clothing for achieving active camouage. [17][18][19][20][21][22] Besides, wearable displays could be developed based on ECFs through an elaborate design of electrochromic pixels or patterns.…”