Triboelectric nanogenerators (TENGs) show promising potential in energy harvesting and sensing for various electronic devices in multiple fields. However, the majority of materials currently utilized in TENGs are unrenewable, undegradable, and necessitate complex preparation processes, resulting in restricted performance and durability for practical applications. Here, we propose a strategy that combines straightforward chemical modification and electrospinning techniques to construct all-cellulose nanofiber-based TENGs with substantial power output. By using cellulose acetate (CA) as the raw material, the prepared cellulose membranes (CMs) and fluorinated cellulose membranes (FCMs) with different functional groups and hydrophobic properties are applied as the tribopositive and tribonegative friction layers of FCM/CM-based triboelectric nanogenerators (FC-TENGs), respectively. This approach modulates the microstructure and triboelectric polarity of the friction materials in FC-TENGs, thus enhancing their triboelectric charge densities and contact areas. As a result, the assembled FC-TENGs demonstrate enhanced output performance (94 V, 8.5 µA, and 0.15 W/m2) and exceptional durability in 15,000 cycles. The prepared FC-TENGs with efficient energy harvesting capabilities can be implemented in practical applications to power various electronic devices. Our work strengthens the viability of cellulose-based TENGs for sustainable development and provides novel perspectives on the cost-effective and valuable utilization of cellulose in the future.

For a long time, the potential application of gel-based ionic devices was limited by the problem of liquid leakage or evaporation. Here, we utilized amorphous, irreversible and reversible cross-linked polyTA (PTA) as a matrix and lithium bis(trifluoromethane sulfonamide) (LiTFSI) as an electrolyte to prepare a stretchable (495%) and self-healing (94%) solvent-free elastomeric ionic conductor. The liquid-free ionic elastomer can be used as a stable strain sensor to monitor human activities sensitively under extreme temperatures. Moreover, the prepared elastic conductor (TEOA0.10-PTA@LiTFSI) was also considered an electrode to assemble with self-designed repairable dielectric organosilicon layers (RD-PDMS) to develop a sustainable triboelectric nanogenerator (SU-TENG) with outstanding performance. SU-TENG maintained good working ability under extreme conditions (-20 °C, 60 °C, and 200% strain). This work provided a low-cost and simple idea for the development of reliable iontronic equipment for human-computer interaction, motion sensing, and sustainable energy.

Sustainable lignin-based electrospun nanofibers were fabricated and used to prepare TENGs, which exhibited enhanced output performance for efficient energy harvesting due to the strong tribo-positivity and high surface area of the nanofibers.

In the field of nanofluidic osmotic power generators, it has been an ultimate but seemingly distant goal to controllably fabricate the different-dimensional confined space including slits, network, nanochannels or their composition to control the ion transport. We demonstrated ion transport behaviors through ultimately 2D lamellar MXene/3D network bacterial nanocellulose nanofiber composite Janus membranes under the different transmembrane concentration gradient. The heterogeneous multilayers Janus membrane comprised effectively stacked hydrophobic MXene to hydrophilic bacterial nanocellulose (BNC). The asymmetric cations transport phenomena were explained in terms of asymmetric surface charges polarization in the confined space. Our results provided a facile and general strategy for studying the effects of membrane-scale confinement, which was important for the development of biomimetic energy conversion, ionic seizing, chemical sensing and other nanoscale technologies.

To achieve environmental sustainability, cellulose-based functional materials have been extensively used in advanced electronic devices, such as pressure sensor and triboelectric nanogenerator (TENG). Here, we fabricate the surface-microstructured cellulose films (M-CFs) by facile regeneration and hot pressing combined with screen mesh templating. Through simple carbonization, the M-CFs are further converted into the surface-microstructured carbonized cellulose films (M-CCFs) with a good conductivity but maintain the original array concave-pits on surface. These constructed microstructures, which are tunable via controlling the screen mesh's aperture, endow the assembled electronics with adjustable and improved working performance. The pressure sensors with M-CCFs as active materials exhibit an enhanced sensitivity in a wide working range and promising potentials for applications in motions detection and healthcare. The TENGs with M-CFs as tribo-positive friction layers demonstrate higher electrical output and an efficient energy harvesting. Our work provides novel insights into the design and construction of cellulose-based functional films for eco-friendly advanced applications.

For sustainability and environmental friendliness, the renewable biomaterials including cellulose have been widely used in flexible electronics, such as pressure sensors. Herein, the carbonized bacterial nanocellulose with excellent conductivity and wood-derived cellulose nanofibrils are combined to prepare the aerogel through directional ice-templating and freeze-drying. The obtained composite aerogel, which has a porous structure and aligned channels, is further employed as an active layer to prepare the resistive-type pressure sensor on a paper substrate. This pressure sensor exhibits remarkable flexibility, fast response, reliability, and especially adjustable sensitivity in a wide pressure range (0-100 kPa). In addition, the sensor's working mechanism and potential applications, such as motion detection, footstep recognition, and communication with smartphones via Bluetooth, are also well demonstrated. Moreover, this work provides novel insights into the development of green pressure sensors and the utilization of sustainable natural biomaterials in high-tech fields.

纤维素纸基功能材料近年来广泛用于柔性电子、光电子、能源与传感等高新科技领域。本文对比总结了纤维素纸功能化制备的常用技术手段,重点介绍了纤维素功能纸在太阳能电池、生物燃料电池和摩擦纳米发电机等能源转化领域的应用,最后指出了纤维素纸基功能材料目前存在的问题并展望了其发展前景。

As over exposure of the earth to ultraviolet (UV) light and increased amount of petroleum-based plastic waste, biodegradable UV-blocking materials are desired for diverse sustainable applications. The corncob residue from xylitol production (CRXP), as a kind of lignocellulosic waste, is mainly composed of cellulose and lignin. Here, we developed a series of CRXP films through a top-down approach (i.e., tunable delignification and regeneration) without any additional additives. Regenerated films, prepared from treated CRXP with lignin contents of 4.4%–29.7%, had excellent UV-blocking capability: 68.6–99.2% for UVB (290–320 nm) and 47.1–98.2% for UVA (320–400 nm). Moreover, these films showed high optical transparency (50.6–86.6%), enhanced water vapor barrier property (2.17–2.76 × 10–11 g cm cm−2 s−1 mmHg−1), great surface hydrophobicity (water contact angle = 73.3°–86.6°), and good thermal stability. Overall, our sustainable UV-blocking films based on CRXP have potential applications in the fields of electronics, food packaging, windshields, and so forth. This study provides new insights into converting lignocellulosic waste directly to high value-added functional bioproducts.

纤维素是植物细胞壁的主要组分之一,是由葡萄糖通过1,4-β糖苷键连接而成的均一聚糖,广泛应用于生产酯类、醚类等纤维素基化工产品。纤维素基产品的制备及应用与其溶解程度密切相关,探究纤维素溶解机理,寻找一种绿色高效的纤维素溶剂至关重要。综述了当前国内外学者们对纤维素溶解机理的解释（氢键破坏理论）以及可能影响溶解的因素（化学热力学、化学动力学、结晶度、纤维素两亲性、电荷数和温度）,在此基础上探讨了导致纤维素水溶性差的原因,提出了在复杂体系中除了氢键作用以外,还需要综合考虑范德华力、疏水性相互作用的影响。同时,总结了纤维素在离子液体中溶解机理方面存在的争议,其中关于氢键理论还存在一定问题,动力学控制理论尚不明确,阳离子在溶解过程所起的作用被忽视,指出离子液体阳离子的两亲性是纤维素溶解的关键因素。基于纤维素的两亲性及两亲性溶剂促进纤维素溶解的重要理论,提出了应重点寻找新型两亲性溶剂的观点,为未来寻求高效、环境友好、成本低廉的纤维素溶剂指明了方向。

Carbon aerogels possess low density, high conductivity, and excellent electrochemical properties, which have potential applications in sensor and energy storage. However, the fabrication methods of carbon aerogels are very complicated, and the applications are usually restricted by their low compressibility, fragile structure, and poor electrical property. Herein, we report a very facile approach for the preparation of compressible, fatigue resistant, conductive, and pressure-sensitive carbon aerogels by pyrolysis of cellulose nanofibers aerogel using melamine foams as the skeleton. The wet aerogels are dried directly in ambient pressure without any volume shrinkage, which is remarkably contrasted to the complex and time-consuming drying process of traditional aerogels. The resulting carbon aerogels exhibit excellent performance, including a low density of 11.23 mg cm(-3), high electrical conductivity of 0.378 S cm(-1), high sensitivity of 1.841 kPa(-1), and outstanding mechanical properties. The assembled carbon aerogel sensors can monitor human activities and pulse vibration, demonstrating the great potential application in wearable devices. Moreover, the high nitrogen content and hydrophilic property enable the carbon aerogels to be used as compressible electrodes with a specific and areal capacitance of 92.2 F g(-1) and 461 mF cm(-2), respectively, showing the promising prospect in flexible supercapacitors.

Deep eutectic solvents (DESs), which are a novel class of sustainable designer solvents, have attracted considerable attentions in the field of cellulose chemistry. Due to their low cost and analogous physico-chemical properties to ionic liquids, DESs are expected to be alternative solvents for dissolving cellulose. However, at present, the solubility of cellulose in DESs is much lower than in most ionic liquids. In this mini-review, we briefly summarize the current state of knowledge about cellulose dissolution in DESs. By comparing with similar solvents, it was found that the components of current DESs are usually involved in hydrogen bond interaction making difficult their interaction with the hydrogen bond network of cellulose. Accordingly, we propose a strategy that the components which have good hydrogen bond accepting ability, such as Cl-, OAc-, HCOO-, (MeO)(2)PO2-, morpholine and imidazole, are promising choices to form DESs for cellulose dissolution. Ultrasound-assisted treatment and adding a surfactant are effective ways to promote cellulose solubility by enhancing the permeability of DESs.

The economically viable synthesis of levulinic acid (LA), a promising and valuable renewable biomass-derived platform for bioproducts, with high carbon efficiency is a challenge. A direct and highly effective catalytic system for conversion of xylose residues (XRs) into LA under mild conditions by using FeCl3 as catalyst and cheaply available NaCl as promoter has been developed. The NaCl solution exhibits high carbon efficiency in LA (68.0 mol %) when compared with the non-NaCl systems (48.5 mol %) due to the moderate increase of the acidity and the higher viscosity of the NaCl system than water. The experimental results demonstrated that the presence of NaCl caused no distinctive changes on reaction pathways but increased the dissolution rate and the hydrolysis rate of XRs cellulose. Moreover, further integration of our degradation process with a reactive extraction step makes energy-efficient separation of LA. The NaCl solutions easily and efficiently extracted LA into LA-derived solvent 2-methyltetrahydrofuran from aqueous solutions. The efficiency and integration of the reaction process presented a great potential for LA production from renewable biomass with the aid of concentrated seawater.

The application of biotechnology in pulp and papermaking industry has been obtained more and more attention,especially the role of hemicellulase in pulp bleaching.Now xylanase bio-bleaching has become a more reliable technology,and it has been widely used in the pulp and papermaking industry.The development of xylanase biobleaching technology of pulps was introduced in this paper,and the mechanism of xylanase-boosting bleaching,bleaching sequences and parameters commonly used in industry of xylanase were discussed.