Ultralight, Elastic, Hybrid Aerogel for Flexible/Wearable Piezoresistive Sensor and Solid–Solid/Gas–Solid Coupled Triboelectric Nanogenerator

Abstract

Aerogels have been attracting wide attentions in flexible/wearable electronics because of their light weight, excellent flexibility, and electrical conductivity. However, multifunctional aerogel-based flexible/wearable electronics for human physiological/motion monitoring, and energy harvest/supply for mobile electronics, have been seldom reported yet. In this study, a kind of hybrid aerogel (GO/CNT HA) based on graphene oxide (GO) and carboxylated multiwalled carbon nanotubes (CMWCNTs) is prepared which can not only used as piezoresistive sensors for human motion and physiological signal detections, but also as high performance triboelectric nanogenerator (TENG) coupled with both solid-solid and gas-solid contact electrifications (CE). The repeatedly loading-unloading tests with 20 000 cycles exhibit its high and ultrastable piezoresistive sensor performances. Moreover, when the obtained aerogel is used as the electrode of a TENG, high electric output performance is produced due to the synergistic effect of solid-solid, and gas-solid interface CEs (3D electrification: solid-solid interface CE between the two solid electrification layers; gas-solid interface CE between the inner surface of GO/CNT HA and the air filled in the aerogel pores). This kind of aerogel promises good applications for human physiological/motion monitoring and energy harvest/supply in flexible/wearable electronics such as piezoresistive sensors and flexible TENG.

Hybrid Aerogel Triboelectric Nanogenerator Based on the Synergistic Effect of Solid–Solid/Gas–Solid Triboelectricity and Piezoelectric Polarization

“…Meanwhile, the butyronitrile layer lost electrons because of its relative positive electron affinity, as shown in Figure b­(I). It is worth noting that when the PTFE layer is in contact with the butyronitrile layer, the BTO HA electrode is compressed, causing two types of contacts: the solid–solid interface contact (PTFE layer and butyronitrile layer) and gas–solid contact (inner surface of the BTO HA and the air filled in the aerogel pores). , The gas–solid contact led to the charge transfer from air to the relatively negative BTO HA, resulting in the accumulation of negative charges inside the BTO HA and positive air charge in the aerogel pores. It should also be noted that BTO NPs is a typical kind of piezoelectric material.…”

Cross-linked Polyimide Nanofibrous Aerogels with Hierarchical Cellular Structure for Thermal Insulation

“…PiNFAs PI (4) where P stands for porosity, ρ PiNFAs is the bulk density of PiNFAs, and ρ PI is the density of the polymer in the bulk state (1.31 g cm −3 ) determined by a Micromeritics Accupyc II 1340 gas pycnometer. The compression test of the PiNFA specimens was conducted on TENSION RFT-1210 (A&D Co., Tokyo, Japan) equipped with two flat-surface compression stages and a cell load of 100 N. Cylindrical samples with a diameter of approximately 20 mm and a height of 16 mm were used for these tests.…”

“…Aerogels generally exhibit low density, transparency, and low thermal conductivity. Aerogels are actively investigated for various applications such as thermal insulation, electronics, catalysis, and separation. ,,,,, Aerogel-based materials with a well-controlled pore structure, mechanical properties, and surface characters are particularly important for such applications. However, the intrinsic brittleness and high production costs of the traditional aerogels significantly restrict their practical applications.…”

Self-Assembled Porous-Reinforcement Microstructure-Based Flexible Triboelectric Patch for Remote Healthcare

“…The birth of triboelectric nanogenerators (TENGs), based on the coupling effect of triboelectrification and electrostatic induction, brings an effective strategy to achieve self-powered sensing [11,12]. It has been extensively developed in recent years due to its natural advantages in terms of a wide range of material choices and the absence of electromagnetic interference [13][14][15]. Optimizing the mechanical properties of TENGbased sensors by building micro-and nano-structures is considered an effective way to improve sensing performance [16,17].…”