Xin Zhao

Ultra-thin, wood-derived carbon electrodes have long been plagued by mechanical brittleness and discontinuous conductive networks. In this study, larch shavings were employed as the starting matrix, wherein a delignification process was implemented to simultaneously enhance the toughness of the cellulose skeleton and regulate the anisotropic lumen channels. Rigid nanocellulose (NC) and flexible chitosan (CS) were further introduced into these channels. Through multi-component physical entanglement and strong hydrogen-bonding cross-linking, a dense dual-network structure was successfully constructed, which significantly improved the toughness and enhanced the network continuity of the carbonaceous skeleton. Consequently, the tensile strength of the prepared ultra-thin precursor (BDW-CSNC) reached an outstanding 916.56 MPa, thereby effectively buffering the volume shrinkage and cell wall damage during the subsequent pyrolysis process, and enabling the derived free-standing carbon skeleton to maintain a high tensile strength of 89.28 MPa. Electrochemical evaluations demonstrated that the BDW-CSNC-900 electrode exhibited an exceptional areal capacitance of 2857.1 mF·cm⁻² at a current density of 1 mA·cm⁻², along with a superb rate capability (87.8% capacitance retention at 60 mA·cm⁻²) in a three-electrode configuration. Furthermore, the assembled symmetric supercapacitor delivered a high areal capacitance of 1194.5 mF·cm⁻², an outstanding areal energy density of 165.90 μWh·cm⁻², and an excellent areal power density of 0.50 mW·cm⁻². This work provides a novel structural design strategy for developing high-performance, ultra-thin, and self-supporting biomass-derived energy storage devices.

Ultra-thin, wood-derived carbon electrodes have long been plagued by mechanical brittleness and discontinuous conductive networks. In this study, larch shavings were employed as the starting matrix, wherein a delignification process was implemented to simultaneously enhance the toughness of the cellulose skeleton and regulate the anisotropic lumen channels. Rigid nanocellulose (NC) and flexible chitosan (CS) were further introduced into these channels. Through multi-component physical entanglement and strong hydrogen-bonding cross-linking, a dense dual-network structure was successfully constructed, which significantly improved the toughness and enhanced the network continuity of the carbonaceous skeleton. Consequently, the tensile strength of the prepared ultra-thin precursor (BDW-CSNC) reached an outstanding 916.56 MPa, thereby effectively buffering the volume shrinkage and cell wall damage during the subsequent pyrolysis process, and enabling the derived free-standing carbon skeleton to maintain a high tensile strength of 89.28 MPa. Electrochemical evaluations demonstrated that the BDW-CSNC-900 electrode exhibited an exceptional areal capacitance of 2857.1 mF·cm⁻² at a current density of 1 mA·cm⁻², along with a superb rate capability (87.8% capacitance retention at 60 mA·cm⁻²) in a three-electrode configuration. Furthermore, the assembled symmetric supercapacitor delivered a high areal capacitance of 1194.5 mF·cm⁻², an outstanding areal energy density of 165.90 μWh·cm⁻², and an excellent areal power density of 0.50 mW·cm⁻². This work provides a novel structural design strategy for developing high-performance, ultra-thin, and self-supporting biomass-derived energy storage devices.

The mechanism by which metal cation radius governs the lignin dissociation and its structural evolution for lignocellulose fractionation in metal chloride/lactic acid (LA) deep eutectic solvents (DESs) remains insufficiently understood. In this work, LA and a series of metal chloride/LA DES systems (CaCl2/LA, FeCl2/LA, and ZnCl2/LA) were systematically constructed to elucidate the effect of cation radius on poplar fractionation. The results showed that a progressive decrease in cation radius led to a substantial enhancement in lignin dissociation (from 22.92% to 97.13%) and hemicellulose removal (from 10.12% to 85.44%). Mechanistic analysis revealed that smaller-radius cations enhanced DES polarization and coordination effects, thereby facilitating β-O-4 ether bond cleavage. Consequently, the condensed lignin structure and grafted lactic acid molecular respectively facilitated the nucleation and growth state for the lignin nanoparticles (LNPs) assembly process. The prepared LNPs were further used for Pickering emulsion stabilization, exhibiting high emulsion stability and tunable particle size. The cellulose-rich residues were upgraded into lignin-containing cellulose nanofiber films, and exhibiting tensile strengths of up to 120 MPa. Overall, this study elucidates the critical regulatory role of cation radius in DES-mediated poplar pretreatment and provides a theoretical foundation for developing green, efficient metal cation-based DES lignocellulose refining strategies.

Ultra-thin wood-based carbon electrodes are attractive candidates for energy storage due to their natural directional channels, renewable resources and controllable thickness. However, their practical application has long been hindered by critical issues such as material brittleness, discontinuous conductive networks, and slow ion transport kinetics. In this study, a synergistic strategy of "component removal-internal reconstruction-pore regulation" strategy is proposed. Using larch wood shavings as a precursor, an ultra-thin, self-supporting, hierarchically porous wood carbon electrode was successfully constructed by delignification pretreatment combined with nanocellulose compositing and gradient carbonization process. Within this strategy, delignification effectively mitigates material brittleness while preserving the wood’s natural porous architecture. The introduction of nanocellulose serves a dual purpose: it acts as a reinforcing agent to enhance the toughness and structural integrity of the carbon skeleton, and simultaneously refines the pore structure as it carbonizes. Finally, an optimal balance between micropores and mesopores was achieved by carbonization at 1000 oC. The results revealed that the BDW-NC-1000 electrode exhibits excellent area specific capacitance (2827.4 mF·cm-2@0.5 mA·cm-2) and remarkable rate capability (109.9% capacitance retention at 10 mA·cm-2) in the three-electrode system. The assembled symmetrical supercapacitor has a high energy density (276500 μWh·L-1) and power density (12600 mW·L-1) in 1 M KOH electrolyte, and exhibits ultra-high cycle stability (the capacitance retention rate is as high as 99.56% after 5000 cycles). This work provides a novel strategy for designing high-performance, ultra-thin self-supporting biomass carbon electrodes, and effectively promoting the high-value utilization of wood waste resources in advanced energy storage devices.

Ultra-thin wood-based carbon electrodes are attractive candidates for energy storage due to their natural directional channels, renewable resources and controllable thickness. However, their practical application has long been hindered by critical issues such as material brittleness, discontinuous conductive networks, and slow ion transport kinetics. In this study, a synergistic strategy of "component removal-internal reconstruction-pore regulation" strategy is proposed. Using larch wood shavings as a precursor, an ultra-thin, self-supporting, hierarchically porous wood carbon electrode was successfully constructed by delignification pretreatment combined with nanocellulose compositing and gradient carbonization process. Within this strategy, delignification effectively mitigates material brittleness while preserving the wood’s natural porous architecture. The introduction of nanocellulose serves a dual purpose: it acts as a reinforcing agent to enhance the toughness and structural integrity of the carbon skeleton, and simultaneously refines the pore structure as it carbonizes. Finally, an optimal balance between micropores and mesopores was achieved by carbonization at 1000 oC. The results revealed that the BDW-NC-1000 electrode exhibits excellent area specific capacitance (2827.4 mF·cm-2@0.5 mA·cm-2) and remarkable rate capability (109.9% capacitance retention at 10 mA·cm-2) in the three-electrode system. The assembled symmetrical supercapacitor has a high energy density (276500 μWh·L-1) and power density (12600 mW·L-1) in 1 M KOH electrolyte, and exhibits ultra-high cycle stability (the capacitance retention rate is as high as 99.56% after 5000 cycles). This work provides a novel strategy for designing high-performance, ultra-thin self-supporting biomass carbon electrodes, and effectively promoting the high-value utilization of wood waste resources in advanced energy storage devices.

Fe and nitrogen-doped carbon nanotubes boost wood-derived Co catalysts to achieve low overpotentials (OER: 411/440; HER: 305/368 mV) at 500/800 mA cm ⁻² in water splitting, highlighting wood's potential for high-value electrocatalytic applications.

Optimizing the electronic structure is pivotal in augmenting the intrinsic catalyst activity.

The previous research addressed the waste problem of agriculture and forestry residues by exploring the efficient utilization of liquefied soybean straw in supercapacitor. The structures of the liquefied soybean straw were controlled by coupling microwave hydrothermal treatment with carbonization under the influence of a C₃N₄ bifunctional template. What′s more, C₃N₄ could effectively regulate the pore structures and provide an effective N active site of carbon materials C₃N_4. The obtained N‐SLR Carbon‐700 possess a specific surface area of up to 1593.7 m² g ⁻¹, and the pore size is mainly concentrated in the range of 1.8–2.5 nm, providing efficient ions transmission channels and storage space. Its specific capacitance is up to 261.5 F g⁻¹ (current density of 0.5 A g⁻¹), and the capacity retention is 74.04 % when the current density is expanded by 20 times. In the two‐electrode system, the energy density of N‐SLR Carbon‐700 could reach to 31.3 W h kg⁻¹ at a power density of 360 W kg⁻¹, as well as the energy surface density is maintained at 69 % when the power density is increased by a factor of 20. This work enhances effectively the charging and discharging stability and capacitance value of carbon‐based supercapacitor.