摘要
【目的】基于木材天然的多孔性、亲水性以及优良机械性能,将薄木切片作为柔性的支撑材料和载体材料与2种纳米碳材料有机结合,制备一种新型柔性薄木/纳米碳材料复合电极,并对其微观结构与电导性能进行研究,为木材功能化和高附加值化提供一种新的研究方向。【方法】利用物理切片方式得到完整性和柔韧性良好的薄木切片,再将纳米碳材料氧化还原石墨烯(RGO)、羧基化多壁碳纳米管(CMWCNT)逐层沉积到薄木表面,借助冷场发射扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、四探针电阻率测试仪和电化学工作站等手段研究薄木/纳米碳材料复合电极的微观形貌、化学结构、电导性和电化学性能,重点探索纳米碳材料与薄木切片的附着机制和界面结合机制。【结果】RGO通过非共价π-π堆积在薄木表面形成褶皱状纳米薄膜结构,CMWCNT则呈不规则颗粒状形貌;横切面薄木/纳米碳材料复合电极呈多孔结构,而径、弦切面则为沟壑状结构。薄木沉积纳米碳材料前后表面化学元素无变化,依然为C(284 e V)、O(532 e V)峰,但C/O比例从1.84增加到5.51(RGO)和3.65(CMWCNT)。随着纳米碳材料沉积次数增加,薄木/RGO和薄木/CMWCNT复合电极的附着量和导电率均随之增大,而且在同一沉积次数下,前者的附着量和导电率略大于后者;当沉积次数达到19次时,RGO附着量可达0.68 mg·cm-2,相应的导电率为0.63 S·cm-1;CMWCNT附着量略低于RGO,为0.45 mg·cm-2,相应的导电率为0.50 S·cm-1;导电率与附着量具有良好的线性拟合性。2种柔性薄木/纳米碳材料复合电极在不同弯曲程度下电流基本保持平稳,表明弯曲应力对其电导性能影响很小。【结论】2种纳米碳材料在薄木表面逐层沉积形成纳米层,且与薄木有较强的附着力(氢键作用)。经过纳米碳材料沉积后,薄木表面化学元素C/O比例显著提高,附着量和导电率也随纳米碳材料沉积次数增加而增大。2种薄木/纳米碳材料复合电极柔性良好,且具有良好的弯曲电导稳定性,可作为柔性电极材料在柔性储能器件和柔性可穿戴设备等方面发挥潜在的应用价值。
【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 nanosheetsusing 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 1 s and O 1 s peaks were observed around binding energy of 284 and 532 e V,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.
作者
吕少一
傅峰
郭丽敏
陈志林
常焕君
Lti Shaoyi;Fu Feng;Guo Limin;Chen Zhilin;Chang Huanjun(Key Laboratory of Wood Science and Technology of State Forestry Administration Research Institute of Wood Industry, CAF Beijing 100091)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2017年第11期150-156,共7页
Scientia Silvae Sinicae
基金
国家自然科学基金项目(31400504)
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
wood-based composite material
flexible wood slice based electrode
nano carbon material
microstructure
electrical conductivity
