RESUMO
Electrochromic (EC) devices represent an emerging energy-saving technology, exhibiting the capability to dynamically modulate light and heat transmittance. Despite their promising potential, the commercialization of EC devices faces substantial impediments such as high cost, intricate fabrication process, and low optical contrast inherent in conventional EC materials relying on the ion insertion/extraction mechanism. In this study, we introduce an innovative "electrode-free" electrochromic (EC) device, termed the EECD, which lacks an EC-layer on the electrodes during device assembling and in the bleached state. This device features a simplified fabrication process and delivers superior optical modulation. It achieves a high optical contrast ranging from 68-85% across the visible spectrum and boasts a rapid response time, reaching 90% coloring in just 17 seconds. In addition, EECD exhibits stable cycling for over 10,000 cycles without noticeable degradation and maintains functionality across a broad temperature range (0 °C to 50 °C). Furthermore, the fabricated large-area devices (40 cm × 40 cm) demonstrate excellent tinting uniformity, suggesting excellent scalability of this approach. Our study establishes a paradigmatic breakthrough for EC smart windows.
RESUMO
Compounding functional nanoparticles with highly conductive and porous carbon scaffolds is a basic pathway for engineering many important functional devices. However, enabling uniform spatial distribution of functional particles within a massively conjugated, monolithic and mesoporous structure remains challenging, as the high processing temperature for graphitization can arouse nanoparticle ripening, agglomerations and compositional changes. Herein, we report a unique "popcorn-making-mimic" strategy for preparing a highly conjugated and uniformly compounded graphene@NiFe2O4 composite film through a laser-assisted instantaneous compounding method in ambient condition. It can successfully inhibit the unwanted structural disintegration and mass loss during the laser treatment by avoiding oxidation, bursting, and inhomogeneous heat accumulations, thus achieving a highly integrated composite structure with superior electrical conductivity and high saturated magnetization. Such a single-sided film exhibits an absolute shielding effectiveness of up to 20906 dB cm2 g-1 with 75% absorption rate, superior mechanical flexibility and excellent temperature/humidity aging reliability. These performance indexes signify a substantial advance in EMI absorption capability, fabrication universality, small form-factor and device reliability toward commercial applications. Our method provides a paradigm for fabricating sophisticated composite materials for versatile applications.