All-fiber structure covered with two-dimensional conductive MOF materials to construct a comfortable, breathable and high-quality self-powered wearable sensor system

Abstract

Flexible, wearable self-powered pressure sensors have successfully sparked great interest in a variety of potential applications. However, the fabrication of such a sensor system with ultra-long battery life, ultra-high operational safety, and mechanical flexibility is still a challenge and an urgent need to complete. Here, a hybrid core–shell material of multifunctional three-dimensional carbon nanofiber networks (CNFNs) based on a conductive metal–organic framework (copper catecholate, Cu-CAT) was synthesized by an electrospinning and hydrothermal method for the first time. Meanwhile, with Cu-CAT@CNFNs as the sensitive layer in a flexible pressure sensor, the pressure sensor device exhibited a wide sensing range (0.5 kPa to 60 kPa), high sensitivity (30.40 kPa⁻¹), fast response/recovery time (0.24 s/0.31 s), reliable air permeability, and an excellent stability for repeated press over 5000 cycles. Benefiting from its excellent technical performance, the pressure sensor array could control the light emission of an LED array and effectively capture joint movements, such as fingers. The good news is that the shell–core structure has outstanding potential as an electrode material for supercapacitors (SCs). A SC prepared with a carbon cloth-loaded Cu-CAT (CC/Cu-CAT-NWAs) electrode showed an excellent area capacitance of 264.8 mF cm⁻², and considerable energy and power density of 58.8 μW h cm⁻² and 1.6 mW cm⁻². By connecting solar cells, supercapacitors, and pressure sensors to form a fully flexible self-powered integrated system, it provides new power for the development of smart home appliances in the future.