氮掺杂纳米碳片/木基碳复合材料的原位构筑及其储能性能

In situ fabrication of nitrogen-doped carbon nanosheet/wood-derived carbon composites and their energy storage performance

  • 摘要: 针对木基碳电极垂直孔道利用率低、活性位点不足、离子传输受限及倍率性能欠佳等问题,以椴木加工剩余物为碳骨架,采用Fe基催化剂诱导尿素原位化学气相沉积策略,在木基碳骨架内外表面可控生长氮掺杂二级纳米碳片并构筑分级多孔结构,制备了氮掺杂二级纳米碳片/木基碳复合材料(NCS/WC-T)。结果表明,800℃制备的NCS/WC-800复合材料完整保留了木材垂直贯通大孔结构,并原位生长出均匀致密、交织的羽毛状二维纳米碳片,兼具大比表面积(912 m2·g−1)、高孔容(0.78 cm3·g−1)及适中的N、O含量(分别为8.0at%和8.1at%)。在56 mg·cm−2高负载量下,NCS/WC-800复合材料三电极面积比电容达11504 mF·cm−2,300 mA·cm−2时仍保持6715 mF·cm−2。组装的对称超级电容器在2 mW·cm−2功率密度下实现0.8 mWh·cm−2的面积能量密度;构建的锌离子混合电容器面积比容量达2.2 mAh·cm−2,20,000次循环后保持率为81.3%。研究表明,该策略实现了天然木材定向骨架、二维纳米活性界面与杂原子调控碳结构的一体化构筑,为高负载量生物质基储能复合材料的设计与应用提供了新思路。

     

    Abstract: Aiming to address limited vertical channel utilization, scarce active sites, sluggish ion migration and inferior rate capability of wood-derived carbon electrodes, nitrogen-doped carbon nanosheets/wood-derived carbon composites (NCS/WC-T) were fabricated by employing basswood processing residues as the carbon framework. A urea-assisted Fe-catalyzed in-situ chemical vapor deposition strategy was adopted to controllably grow nitrogen-doped secondary carbon nanosheets on the inner and outer surfaces of the wood-derived carbon framework, thereby forming hierarchically porous architecture. The results showed that the NCS/WC-800 composite prepared at 800℃ perfectly retained the vertically-aligned through-pore structure of natural wood, and uniformly dense and interwoven feather-like two-dimensional nanocarbon sheets were in-situ grown. The composite possessed a specific surface area (912 m2·g−1), high pore volume (0.78 cm3·g−1) and moderate N and O contents (8.0at% and 8.1at%, respectively). At a high mass loading of 56 mg·cm−2, the NCS/WC-800 composite delivered an areal specific capacitance of 11504 mF·cm−2 in a three-electrode system, and remained 6715 mF·cm−2 at 300 mA·cm−2. The assembled symmetric supercapacitor achieved an areal energy density of 0.8 mWh·cm−2 at a power density of 2 mW·cm−2. The constructed zinc-ion hybrid capacitor exhibited an areal specific capacity of 2.2 mAh·cm−2, with a capacity retention of 81.3% after 20,000 cycles. This work verifies that the developed strategy enables the synergistic integration of oriented wood scaffold, two-dimensional active nano-interfaces and heteroatom-modified carbon structure, offering a promising route for designing advanced biomass-based electrode materials toward high-mass-loading energy storage devices.

     

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