关键词: 木基复合材料, 柔性薄木电极, 纳米碳材料, 微观结构, 电导性能

Abstract: [Objective] Wood has natural porous characteristics, hydrophilic and excellent mechanical properties. As a flexible supporting material and carrier material, wood slice was combined with two kinds of nano-carbon material to get a novel flexible wood slice/nano carbon material composite electrode material. Microstructure and electrical conductivity of this electrode material was studied here. This research will provide a new direction for the functional and high value-added of wood.[Method] Wood slice with good integrity and flexibility can be got by cutting wood into thin slices. The nano carbon material RGO and CMWCNT can be deposited on the surface of wood slice. The microstructure, chemical structure, conductivity and electrochemical properties of wood slice/nano carbon material composite electrode were studied by SEM, XPS, 4-point probe resistivity measurement system and electrochemical workstation. The adhesion mechanism and interface bonding mechanism between wood slice and nano carbon material were also studied here seriously.[Result] The RGO layer attached to the wood slice formed wrinkled nano-films by means of the dense packing of RGO nanosheets using π-π stacking, while CMWCNT formed irregular granular morphology. Wood transverse section slice/nano carbon material composite electrode showed the porous structure, while the same electrode based on wood radial section slice and wood tangential section slice had gully-like morphology. The surface element type had no change before and after the nano carbon material coated. The C 1s and O 1s peaks were observed around binding energy of 284 and 532 eV, while the C/O ratio increased from 1.84 to 5.51 (RGO) and 3.65 (CMWCNT). As the deposition times of nano carbon material increased, the mass loading and conductivity of wood slice/RGO and wood slice/CMWCNT increased too. Meanwhile, the mass loading and conductivity of wood slice/RGO were greater than that of wood slice/CMWCNT under the same deposition times. When the deposition times reached 19 within the scope of this study, mass loading and conductivity of wood slice/RGO achieved 0.68 mg·cm^-2 and 0.63 S·cm^-1, while values of wood slice/CMWCNT were 0.45 mg·cm^-2 and 0.50 S·cm^-1, respectively. There was a good linear fit between conductivity and mass loading. The current of two kinds of wood slice/nano carbon material composite electrode kept stable at different bending degrees, indicating that the bending stress had little influence on the conductivity.[Conclusion] Two kinds of nano carbon material formed nano layer on the surface of the wood slice by layer-by-layer deposition. This nano layer had strong adhesion with wood slice, which may be ascribed to the strong hydrogen bond interaction. After the deposition of nano carbon materials, the proportion of chemical elements C/O on the surface of the wood slice increased significantly. The amount of mass loading and conductivity also increased with the increase of deposition times. The two kinds of wood/carbon nano composite electrode had good flexibility and good bending conductivity stability. As a flexible electrode, it had a potential application in flexible energy storage device and flexible wearable equipment.

Key words: wood-based composite material, flexible wood slice based electrode, nano carbon material, microstructure, electrical conductivity