Cellulose Nanofiber-Reinforced MXene Membranes as Stable Friction Layers and Effective Electrodes for High-Performance Triboelectric Nanogenerators

Abstract

In this work, MXene films incorporating cellulose nanofibers (CNFs) with a spider-web-like structure were fabricated using a facile vacuum-assisted filtration method. The CNFs significantly improved the flexibility and stability of the MXene membranes. The resulting composites functioned well as electrodes and friction layers in triboelectric nanogenerators (TENGs) when paired with either polytetrafluoroethylene (PTFE) as an electropositive material or nylon as an electronegative material. A membrane containing 20 wt % CNFs in conjunction with PTFE was extremely effective during the prolonged operation of a TENGs, generating an output voltage in excess of 1120 V at a frequency of 3.5 Hz. The surface charge density of this device was as high as 100 μC m–2. When paired with nylon, the MXene/CNF film produced a surface charge density of over 60 μC m–2. The microstructures on the rough surface of these membranes, together with the presence of −F and other polar terminations on the MXene, are responsible for the high performance of the nanocomposite. This work demonstrates that MXenes are not necessarily equivalent to PTFE within the triboelectric series and suggests that the MXene-based friction layer could greatly enhance the performance of TENGs.

Advanced Functionalized Materials Based on Layer‐by‐Layer Assembled Natural Cellulose Nanofiber for Electrodes: A Review

“…In general, the rough and porous nature facilitates the loading of active materials and the transport of ions. [153,154] For example, the multilayer composite electrode fabricated via the assembling of NH 2 -and COOH-functionalized CNT and dioleamidestabilized LiFePO 4 nanoparticles (DA-LFP NPs) onto the surface of cellulose textiles (C-textiles) using LbL displayed a remarkable specific capacitance of 196 mAh g −1 and high rate capability; this electrode displayed highly flexible mechanical properties since the large area surface of porous textile prevents the agglomeration or precipitation of active materials, and the excellent interface design provides better charge transfer kinetics, [20] as shown Figure 11c-f. However, the thin film structures with minimum possible defects (tens to hundreds of nanometers) are necessary to facilitate the desired charge transport, like sliver mirror reaction [155] and optoelectronic materials [156,157] onto paper.…”

Flexible, humidity- and contamination-resistant superhydrophobic MXene-based electrospun triboelectric nanogenerators for distributed energy harvesting applications

“…Besides, two-dimensional (2D) Ti 3 C 2 T x MXenes with prominent properties such as high electronegativity and surface-charge density, metallic electrical conductivity, tunable surface chemistry, and a large specific surface area have been widely studied with promising results of greater charge-trapping ability, swift transfer of induced charges, and a large frictional contact area between triboelectric layers. 2,17,18 According to previous investigations, MXene-based TENG performance has been significantly improved based on the above-mentioned strategies. 19,20 In particular, with the morphological modification of MXenes, one-dimensional MXene/polymer composite nanofibers have attracted tremendous attention for the reason that electrospun nanofibers possess a porous, rough structure and a high specific surface area, promoting the frictional contact area and charge accumulation process.…”

A self-assembled molecularly triboelectronegative cellulose nanofiber material with ultrahigh contact triboelectrification for the design of green triboelectric nanogenerators

“…[6][7][8][9][10] However, the triboelectronegative tribolayers of traditional TENGs are usually made of polymer materials such as polytetrauoroethylene (PTFE), polydimethylsiloxane (PDMS), polystyrene (PS) and other non-degradable materials, which increases the risk of environmental pollution. [11][12][13][14][15] In order to solve this problem, researchers are committed to developing new bio-based tribolayer materials including starch, cellulose, sodium alginate, and silk protein to replace traditional polymer materials. [16][17][18][19][20] To a certain extent, the special characteristics of these materials, such as abundant sources, simple preparation, degradability, and moisture resistance, have made outstanding contributions to the development of green TENGs.…”

“…6–10 However, the triboelectronegative tribolayers of traditional TENGs are usually made of polymer materials such as polytetrafluoroethylene (PTFE), polydimethylsiloxane (PDMS), polystyrene (PS) and other non-degradable materials, which increases the risk of environmental pollution. 11–15 In order to solve this problem, researchers are committed to developing new bio-based tribolayer materials including starch, cellulose, sodium alginate, and silk protein to replace traditional polymer materials. 16–20…”