Jia MengYing, Cheng Chen, Cui Linlin, Li Yue, Jin Xiao-Juan
MOE Key Laboratory of Wooden Material Science and Application, Beijing Key Laboratory of Lignocellulosic Chemistry, MOE Engineering Research Center of Forestry Biomass Materials and Bioenergy, Beijing Forestry University 35 Qinghua East Road, Haidian 100083 Beijing China
RSC Adv. 2020 Jan 22;10(6):3544-3553. doi: 10.1039/c9ra07682d. eCollection 2020 Jan 16.
A novel composite electrode has been fabricated by the direct deposition of MnO onto graphene networks surrounding a paper fiber (PFG). The paper fiber between graphene sheets could be used as a flexible substrate for MnO nanoparticles, and the microscopic morphologies and electrochemical performances of the MnO@PFG electrodes were tuned regulating the deposition current densities and deposition times. 3D graphene on PFG served as a highly conductive backbone with a high surface area for the deposition of the MnO nanoparticles, which provided high accessibility to electrolyte ions for shortening the diffusion paths. The MnO-10-600 s@PFG composite electrode achieved a maximum specific capacitance of 878.6 mF cm with an MnO loading mass of 3.62 mg cm (specific capacitance of 187.7 F g) at a current density of 0.5 mA cm in a 1 M NaSO aqueous solution. Additionally, the MnO-10-600 s@PFG composite material with the most favorable composite ratio exhibited the highest energy density of 61.01 mW h cm, maximum power density of 1249.78 mW cm, excellent capacitance retention with no more than 7% capacitance loss after 10 000 cycles and good mechanical flexibility (about 91.06% of its original capacitance after 500 bending times). By combining the electric double layer capacitance of graphene networks with the pseudocapacitance of the MnO nanostructures, the flexible electrode showed much enhanced electrochemical capacitance behaviors with robust tolerance to mechanical deformation; thus, it is promising for being woven into textiles for wearable electronics.
通过将MnO直接沉积在围绕纸纤维（PFG）的石墨烯网络上，制备了一种新型复合电极。石墨烯片之间的纸纤维可作为MnO纳米颗粒的柔性基底，通过调节沉积电流密度和沉积时间来调控MnO@PFG电极的微观形貌和电化学性能。PFG上的三维石墨烯作为高导电性骨架，具有高表面积用于MnO纳米颗粒的沉积，这为电解质离子提供了高可达性，从而缩短了扩散路径。在1 M Na₂SO₄水溶液中，电流密度为0.5 mA cm⁻²时，MnO-10-600 s@PFG复合电极在MnO负载质量为3.62 mg cm⁻²（比电容为187.7 F g⁻¹）的情况下，实现了878.6 mF cm⁻²的最大比电容。此外，具有最有利复合比的MnO-10-600 s@PFG复合材料表现出最高能量密度为61.01 mW h cm⁻³、最大功率密度为1249.78 mW cm⁻³、在10000次循环后电容损失不超过7%的优异电容保持率以及良好的机械柔韧性（在500次弯曲后约为其原始电容的91.06%）。通过将石墨烯网络的双电层电容与MnO纳米结构的赝电容相结合，该柔性电极表现出大大增强的电化学电容行为，对机械变形具有很强的耐受性；因此，有望编织成用于可穿戴电子设备的纺织品。
