2D Materials‐Based Electrochemical Triboelectric Nanogenerators

Abstract

The integration of 2D materials in triboelectric nanogenerators (TENGs) is known to increase the mechanical‐to‐electrical power conversion efficiency. 2D materials are used in TENGs with multiple roles as triboelectric material, charge‐trapping fillers, or as electrodes. Here, novel TENGs based on few‐layers graphene (FLG) electrodes and stable gel electrolytes composed of liquid phase exfoliated 2D‐transition metal dichalcogenides and polyvinyl alcohol are developed. TENGs embedding FLG and gel composites show competitive open‐circuit voltage (≈ 300 V), instant peak power (530 mW m−2), and stability (> 11 months). These values correspond to a seven‐fold higher electrical output compared to TENGs embedding bare FLG electrodes. It is demonstrated that such a significant improvement depends on the high electrical double‐layer capacitance (EDLC) of FLG electrodes functionalized with the gel composites. The wet encapsulation of the TENGs is shown to be an effective strategy to increase their power output further highlighting the EDLC role. It is also shown that the EDLC is dependent upon the transition metal (W vs Mo) rather than the relative abundance of 1T or 2H phases. Overall, this work lays down the roots for novel sustainable electrochemical‐(e)‐TENGs developed exploiting strategies typically used in electrochemical capacitors.

Scalable Production of 2D Material Heterostructure Textiles for High-Performance Wearable Supercapacitors

“…Figure d shows the high-resolution C 1s spectra, which reveals peaks for graphene flakes, dominated by C–C and C–CC in aromatic rings (∼284.6 eV). The high-resolution XPS spectrum of the exfoliated MoS 2 acquired in the chalcogen binding energy region (226–232 eV) exhibits two obvious peaks at ∼227 and ∼230.5 eV, corresponding to Mo 3d 5/2 and Mo 3d 3/2 , respectively, indicating the characteristic of a Mo 4+ state in MoS 2 (Figure e). The peaks of S 2p 3/2 and S 2p 1/2 were located at ∼164.0 and ∼165.1 eV, respectively, with a spin–orbit splitting of 1.1 eV, revealing the S 2 – in MoS 2 , (Figure f).…”

Polyoxometalate-Modified g-C3N4 Composites with High Work Function for Triboelectric Nanogenerators

“…With the advent of the era of 5G technology, the rapid development of emerging wearable flexible electronics and sensors has increased the demand for renewable, sustainable, and portable power supplies. − To power these numerous electronic devices, people are committed to developing portable power technologies, such as solar cells, , pyroelectric nanogenerators, , piezoelectric nanogenerators, , and triboelectric nanogenerators (TENG). , Among them, TENG is the one that has garnered the most interest among them all because of its ability to capture and transform mechanical vibration, sound waves, water movement, vehicle movement, and human activity in the surrounding environment into electric energy. , To meet the application requirements, various strategies have been proposed to improve the output performance of TENG, such as material design and structural optimization. − From the perspective of material design, it is very important to select the appropriate friction material. , At present, the most widely used friction material organic polymer has a relatively single form, especially in the functionalization and modification of certain difficulties. Therefore, it is necessary to develop new friction materials that are easy to modify and functionalize to improve the performance of TENG.…”

Synthesis of High-Quality Monolayer MoS2 via a CVD Upstream Deposition Strategy for Charge Capture and Collection

“…Compared with traditional electrode materials and other two-dimensional materials, TMDs also show superior potential for applications in energy storage. − They possess several advantages, including a large electrochemically active surface area, tunable high surface area, abundant coordination sites, as well as both “Faradaic” and “non-Faradaic” electrochemical behaviors . These characteristics make TMDs promising materials for high-performance energy harvesting devices, capacitive charging devices, and capacitive mechanical sensors .…”

“…12−14 They possess several advantages, including a large electrochemically active surface area, tunable high surface area, abundant coordination sites, as well as both "Faradaic" and "non-Faradaic" electrochemical behaviors. 15 These characteristics make TMDs promising materials for high-performance energy harvesting devices, 16 capacitive charging devices, 17 and capacitive mechanical sensors. 18 Traditional MoS 2 energy conversion devices, such as hydrovoltaic nanogenerators and friction-based nanogenerators, have demonstrated great potential for the application of two-dimensional materials.…”