Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk natural wood directly into a high-performance structural material with a more than tenfold increase in strength, toughness and ballistic resistance and with greater dimensional stability. Our two-step process involves the partial removal of lignin and hemicellulose from the natural wood via a boiling process in an aqueous mixture of NaOH and NaSO followed by hot-pressing, leading to the total collapse of cell walls and the complete densification of the natural wood with highly aligned cellulose nanofibres. This strategy is shown to be universally effective for various species of wood. Our processed wood has a specific strength higher than that of most structural metals and alloys, making it a low-cost, high-performance, lightweight alternative.

Plasmonic metal nanoparticles are a category of plasmonic materials that can efficiently convert light into heat under illumination, which can be applied in the field of solar steam generation. Here, this study designs a novel type of plasmonic material, which is made by uniformly decorating fine metal nanoparticles into the 3D mesoporous matrix of natural wood (plasmonic wood). The plasmonic wood exhibits high light absorption ability (≈99%) over a broad wavelength range from 200 to 2500 nm due to the plasmonic effect of metal nanoparticles and the waveguide effect of microchannels in the wood matrix. The 3D mesoporous wood with numerous low‐tortuosity microchannels and nanochannels can transport water up from the bottom of the device effectively due to the capillary effect. As a result, the 3D aligned porous architecture can achieve a high solar conversion efficiency of 85% under ten‐sun illumination (10 kW m−2). The plasmonic wood also exhibits superior stability for solar steam generation, without any degradation after being evaluated for 144 h. Its high conversion efficiency and excellent cycling stability demonstrate the potential of newly developed plasmonic wood to solar energy‐based water desalination.

For the first time, two types of highly anisotropic, highly transparent wood composites are demonstrated by taking advantage of the macro-structures in original wood. These wood composites are highly transparent with a total transmittance up to 90% but exhibit dramatically different optical and mechanical properties.

The solar steam process, akin to the natural water cycle, is considered to be an attractive approach to address water scarcity issues globally. However, water extraction from groundwater, for example, has not been demonstrated using these existing technologies. Additionally, there are major unaddressed challenges in extracting potable water from seawater including salt accumulation and long-term evaporation stability, which warrant further investigation. Herein, a high-performance solar steam device composed entirely of natural wood is reported. The pristine, natural wood is cut along the transverse direction and the top surface is carbonized to create a unique bilayer structure. This tree-inspired design offers distinct advantages for water extraction, including rapid water transport and evaporation in the mesoporous wood, high light absorption (≈99%) within the surface carbonized open wood channels, a low thermal conductivity to avoid thermal loss, and cost effectiveness. The device also exhibits long-term stability in seawater without salt accumulation as well as high performance for underground water extraction. The tree-inspired design offers an inexpensive and scalable solar energy harvesting and steam generation technology that can provide clean water globally, especially for rural or remote areas where water is not only scarce but also limited by water extraction materials and methods.

Wood, an earth-abundant material, is widely used in our everyday life. With its mesoporous structure, natural wood is comprised of numerous long, partially aligned channels (lumens) as well as nanochannels that stretch along its growth direction. This wood mesostructure is suitable for a range of emerging applications, especially as a membrane/separation material. Here, we report a mesoporous, three-dimensional (3D) wood membrane decorated with palladium nanoparticles (Pd NPs/wood membrane) for efficient wastewater treatment. The 3D Pd NPs/wood membrane possesses the following advantages: (1) the uniformly distributed lignin within the wood mesostructure can effectively reduce Pd(II) ions to Pd NPs; (2) cellulose, with its abundant hydroxyl groups, can immobilize Pd NPs; (3) the partially aligned mesoporous wood channels as well as their inner ingenious microstructures increase the likelihood of wastewater contacting Pd NPs decorating the wood surface; (4) the long, Pd NP-decorated channels facilitate bulk treatment as water flows through the entire mesoporous wood membrane. As a proof of concept, we demonstrated the use and efficiency of a Pd NPs/wood membrane to remove methylene blue (MB, CHNClS) from a flowing aqueous solution. The turnover frequency of the Pd NPs/wood membrane, ∼2.02 mol·mol·min, is much higher than the values reported in the literature. The water treatment rate of the 3D Pd NPs/wood membrane can reach 1 × 10 L·m·h with a high MB removal efficiency (>99.8%). The 3D mesoporous wood membrane with partially aligned channels exhibits promising results for wastewater treatment and is applicable for an even wider range of separation applications.

mechanism. The large impedance associated with transport for ions and electrons limits the thickness of the electrode usually less than 100 µm. To overcome the issue of charge transport, 1D and 2D nanomaterials (i.e., carbon nanotubes and graphene) have been used to provide fast percolative pathways for electron transport. [16][17][18][19] It is also found that low-tortuosity electrodes can provide fast ion transport, which indeed lead to much-improved rate performance. [ 20,21 ] Wood has a unique anisotropic structure, where there are open channels along the growth direction to help pump water, ions, and other ingredients. Herein, we design a 3D carbon electrode through directly carbonizing wood that is cut perpendicularly to the growth direction. The carbonized wood has the perfect open channels, which lead to a low tortuosity for ion transport. The well-connected carbon also provides excellent path for electron transport with small impedance. In this work, we demonstrated for the fi rst time that ultra-thick, mesoporous carbon with a thickness up to 850 µm and an areal mass of 55 mg cm −2 . The mesoporous carbon not only shows a high specifi c capacity of 270 mA h g −1 but also a high areal capacity of 13.6 mA h cm −2 evaluated as anode for SIB in half cells. The thickness, areal mass, and areal capacity are signifi cantly higher than the values from the state-of-the-art batteries. The ultra-thick wood-derived carbon is also a binder-free, current collector-free electrode that also signifi cant increases the weight percentage of the active mass in SIBs. Excellent cycling performance was demonstrated in full cells based on Na 3 V 2 (PO 4 ) 3 cathode and wood carbon anode. The woodbased freestanding, mesoporous carbon with a unique anisotropic structure is a promising anode in the emerging SIB technology. Note that other biomass has been investigated as the precursors for high-performance SIB anodes, [22][23][24] but the biomass-derived carbons follow traditional battery design with binders coated on current collectors and the areal capacity is much smaller than the reported value in this study. The lowtortuosity wood with the open, ordered channels can also open a range of other energy and environmental-related applications, such as membrane for gas separation, water fi ltration, and fl ow batteries.Wood is one of the most abundant biomass on Earth and has a heterogeneous and anisotropic structure ( Figure 1 a). There are a large number of straight multichannels in the up-growing direction of the tree, leading to a lowest tortuosity, close to one, along the growth direction. Such a unique structure inspires us a new insight for fabricating low-tortuosity carbon based on wood, which can be dramatically different from any other types of macroscopic carbon. As shown in Figure 1 b, a 3D structured carbon electrode is Grid-scale energy storage is critical in the renewable energy landscape due to the intermittent nature of the renewable energy sources such as wind, solar, and others. Compared with many other grid-sca...

Among many other requirements, energy efficient building materials require effective daylight harvesting and thermal insulation to reduce electricity usage and weatherization cost. The most commonly used daylight harvesting material, glass, has limited light management capability and poor thermal insulation. For the first time, transparent wood is introduced as a building material with the following advantages compared with glass: (1) high optical transparency over the visible wavelength range (>85%); (2) broadband optical haze (>95%), which can create a uniform and consistent daylight distribution over the day without glare effect; (3) unique light guiding effect with a large forward to back scattering ratio of 9 for a 0.5 cm thick transparent wood; (4) excellent thermal insulation with a thermal conductivity around 0.32 W m−1 K−1 along the wood growth direction and 0.15 W m−1 K−1 in the cross plane, much lower than that of glass (≈1 W m−1 K−1); (5) high impact energy absorption that eliminates the safety issues often presented by glass; and (6) simple, scalable fabrication with reliable performance. The demonstrated transparent wood composite exhibits great promise as a future building material, especially as a replacement of glass toward energy efficient building with sustainable materials.

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