Biomass-derived carbon is a promising sustainable anode material for sodium-ion batteries (SIBs). Although the electrochemical performance can be improved by introducing functional groups, the selective introduction of single functional groups into biomass carbon remains difficult. Here, we overcome this challenge by developing a wood-derived carbon with selectively introduced CO groups by combining tetramethoxysilane (TMOS) with wood cellulose pulps. The integration of TMOS introduces abundant CO groups into the carbon during the polycondensation and pyrolysis process. The CO groups play a dominant role in anode surface-controlled processes, and this leads to improvements in pseudo-capacity and fast electrode process kinetics. Besides, the introduction of CO groups generates oxygen functional active sites that promote Na + adsorption and creates a sufficiently large graphene interlayer distance. The as-obtained carbon shows a high capacity of 330 mAh g −1 at 40 mA g −1 and excellent cycling stability. Moreover, our strategy is simple and uses wood cellulose pulps as precursors. It therefore enables lowcost and large-scale synthesis of carbon anode materials for SIBs.

The development of nanogenerators (NGs) with optimal performances and functionalities requires more novel materials. Over the past decade, biopolymer nanofibers (BPNFs) have become critical sustainable building blocks in energy-related fields because they have distinctive nanostructures and properties and can be obtained from abundant and renewable resources. This review summarizes recent advances in the use of BPNFs for NG development. We will begin by introducing various strategies for fabricating BPNFs with diverse structures and performances. Then, we will systematically present the utilization of polysaccharide and protein nanofibers for NGs. We will mainly focus on the use of BPNFs to generate bulk materials with tailored structures and properties for assembling of triboelectric and piezoelectric NGs. The use of BPNFs to construct NGs for the generation of electricity from moisture and osmosis is also discussed. Finally, we illustrate our personal perspectives on several issues that require special attention with regard to future developments in this active field.

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Fast water permeable filters with an efficient rejection ratio are desirable for nanoparticle separation and water/air purification. Ultrathin nanoporous filters are effective because of their features, including narrow and tunable pore size distributions capable of handling a high solvent flux. However, it remains challenging to develop antifouling filters that maintain a stable flux with high rejection efficiency over long‐term filtration of nanoparticle solutions. Here, a facile and low‐cost approach is reported to fabricate biocompatible hydrogel filters with interconnected nanofiber network structures through the use of high aspect ratio, wood‐derived nanofibrillated cellulose (NFC). The super‐hydrophilia and high porosity of these materials endow the NFC hydrogel filters (NFC‐HFs) with high solvent permeance. Nanofibrous networks and interconnected nanoporous structures of NFC‐HFs promote efficient rejection and precise size‐selective separation of nanoparticles. Specifically, small and irregular nanopores of NFC‐HFs fail to match the size of relatively large nanoparticles, which ensures a relatively stable flux of the NFC‐HFs over the whole filtration process, even under continuous filtration of highly concentrated nanoparticle solutions.

Figure 5. Wood-based robotic hand and its application in fire rescue. a) Scheme of a hygrothermic wood robotic hand. Digital photographs of a hygrothermic wood robotic hand b) in stretching and c) in grasping; the scale bar is 5 cm. d) The four steps for grabbing a ball using the hygrothermic wood robotic hand at 70 °C. e) Scheme demonstrating the application of the hygrothermic wood actuator in fire rescue. f) Digital photographs of a wooden house used in the rescue simulation scene. g) Four steps of the simulated rescue scene at 170 °C.

As defined by the United Nations, "clean water and sanitation" is one of the 17 sustainable development goals for the improvement of sustainable living. Pollution prevention and the acquisition of clean water are urgent demands that require the joint cooperation of all nations. From a practical standpoint, it is important to develop sustainable systems for oil/water separation because mixtures of oil and water often threaten the environment and endanger biological systems. For example, major oil spills can destroy entire ecosystems and the economic activities that depend on them. [1] Separating oil and water is currently a global challenge. [2][3][4][5][6][7][8][9][10][11][12][13][14] Thus, more effort is required for the construction of effective systems based on functional materials, devices, and techniques that facilitate the sustainable separation of oil/ water mixtures (O/W-Ms) to obtain clean water and to enable the recycling of expensive oil. Water is often "polluted" by oil and forms oil/water layered mixtures (O/W-LMs), oil-in-water emulsions (O/W-Es), and water-in-oil emulsions (W/O-Es). [2] When trace amounts of water is mixed in oil, it is also difficult to remove the water. Different types of O/W-Ms have been separated by filtration and absorption using systems containing various materials with specific structures and wettabilities. These materials are usually porous to facilitate liquid absorption, storage, and transportation.For filtration separation systems, hydrophilic materials that are oleophobic in subaquatic environments are used as filters to retain oil and allow water to pass through, [15][16][17] whereas oleophilic materials that are hydrophobic under oil are used as filters to repel water and enable oil to pass through. [18][19][20][21] For absorption separation systems, various oleophilic and hydrophobic materials are exploited to absorb oil from water. [22][23][24][25][26][27][28] Speed and efficiency are the most critical factors for separation systems, and are widely determined by the method of separation, the structures and performances of the separation materials, and the characteristics, ratios, and amounts of the O/W-Ms. It is also important to achieve continuous and largescale oil/water separation. [28][29][30] Although systems comprising novel materials and devices have been employed for the rapid and efficient separation of oil and water, the exploitation of separation materials still faces many practical challenges. These Separating oil and water remains a serious challenge because various oil/ water mixtures are generated in large quantities by industrial processes, unexpected accidents, and daily life. Various systems containing materials with specific structures and wettabilities have been investigated as possible solutions to this issue. As a sustainable biological material, wood and its derivatives have many advantageous properties for practical applications. The present review mainly focuses on recent progress in using wood-derived systems for sustainable oil/water separ...

Lithium−sulfur batteries are afflicted with capacity fading on account of polysulfide shuttling. A novel cost-effective electrode that can hinder the polysulfide shuttling and realize high active material utilization is highly required. Here, we demonstrate a flexible, electrically conductive, nanostructured, and asymmetric hybrid cathode by integrating a high-aspect-ratio wood nanocellulose and a low-cost commercial carbon nanotube (∼$ 0.2 g −1 ) into an entangled aerogel film. The vacuum filtration combined with lyophilization enables the aerogel film with quite different nanofiber/nanotube packing densities and pore structures at its two sides. The cooperative effects of the entangled building blocks and the asymmetric porous structure of the aerogel film stimulate the simultaneous increase of active sulfur loading, enhancing the electrolyte penetration, alleviating dissolution and shuttling of polysulfide ions, and promoting the fast electron transportation. The as-generated cathode exhibited a capacity fading of 0.01% per cycle over 1000 discharge/charge cycles at a 0.5 C rate (1 C = 1675 mA g −1 ). The average Coulombic efficiency reached ∼99.7%.

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