Carbon-Based Flexible and All-Solid-State Micro-supercapacitors Fabricated by Inkjet Printing with Enhanced Performance

By means of inkjet printing technique, flexible and all-solid-state micro-supercapacitors(MSCs) were fabricated with carbon-based hybrid ink composed of graphene oxide(GO,98.0vol.%) ink and commercial pen ink(2.0vol.%). A small amount of commercial pen ink was added to effectively reduce the agglomeration of theGO sheets during solvent evaporation and the following reduction processes in which the presence of graphite carbon nanoparticles served as nano-spacer to separate GO sheets. The printed device fabricated using the hybrid ink,combined with the binder-free microelectrodes and interdigital microelectrode configuration, exhibits nearly 780%enhancement in areal capacitance compared with that of pure GO ink. It also shows excellent flexibility and cycling stability with nearly 100% retention of the areal capacitance after 10,000 cycles. The all-solid-state device can be optionally connected in series or in parallel to meet the voltage and capacity requirements for a given application.This work demonstrates a promising future of the carbonbased hybrid ink for directly large-scale inkjet printing MSCs for disposable energy storage devices.

高导电水性石墨烯基导电油墨的制备及其应用性能

为解决柔性电子印刷中传统碳系导电油墨导电性能差的问题,通过引用高导电的石墨烯,制备了基于石墨烯/炭黑/石墨三维导电网络结构的水性石墨烯基导电油墨。探讨了分散剂用量、颜基比和干燥处理工艺三个主要因素对导电油墨导电性能的影响。在此基础上,采用低成本的丝网印刷工艺制备了柔性电热纺织品以评估导电油墨的应用性能。结果表明,制备的导电油墨具有较高的导电性能,最低方阻为20Ω/□。以此制备的柔性电热纺织品具有快速的升温能力和优异的电热稳定性、耐疲劳性,在充电宝5V电压下90s左右可以由室温到达稳态温度(60±3)℃,且具有一定的机械柔韧性。所制备的高导电水性石墨烯基导电油墨在柔性可穿戴领域具有较好的实际应用价值。

复合碳系导电油墨的制备及性能研究

目的研究碳纳米管与石墨烯对复合碳系导电油墨性能的影响,开发性能优异的导电油墨。方法分别探究碳纳米管管径尺寸、碳纳米管与石墨烯的配比、油墨中的碳质量分数及油墨涂层厚度对复合碳系导电油墨导电性的影响,并基于实验数据对各影响因素拟合出相应的预测模型。最终确定油墨的优选配比,并对采用优选配比制备的导电油墨涂层进行电热转换测试。结果由石墨烯和管径尺寸为25 nm的多壁碳纳米管为导电填料制备的导电油墨涂层综合导电性能最优,当导电油墨中碳质量分数为2.5%(纳米管质量分数为0.125%、石墨烯质量分数为2.375%)、水性丙烯酸树脂质量分数为5.25%、油墨涂层固化后厚度为0.147 mm时,油墨导电涂层电阻率为0.0893Ω·cm。在外接电压为5 V的条件下,导电油墨的功率为13.49 W,由室温通电工作至100℃仅需13.723 s,油墨涂层发热均匀性满足JG/T 286—2020的要求。结论采用优选配比制备的油墨涂层内部搭建起均匀丰富的导电网络,极大地提升了油墨的导电性,使得油墨电热性能优异。

碳纳米管对碳系导电油墨电热性能的影响

目的 研究碳纳米管对碳系水性导电油墨电热性能的影响,寻找最佳含量的发热油墨。方法 采用单因素法,在原有碳系水性导电油墨中通过添加不同含量的碳纳米管制备多组碳系水性电热油墨。通过测试其SEM、TEM、电热功率、接触角等探究碳系水性电热油墨的最佳制备配方。结果 不同碳纳米管含量的碳系水性电热油墨其发热温度、电功率具有一定的差异。在其他条件一定的情况下,随着碳纳米管含量的增加,碳系水性导电油墨的电热导电性先降低再升高。当碳纳米管质量分数为0.75%时,碳系水性导电油墨的可以达到温度最高(147℃),功率相对较低(4.4 W),此时为导电性最佳碳系水性电热油墨的配方。结论 在导电油墨中添加适量的碳纳米管可改善油墨的加热性能。

丙烯酸树脂基导电油墨正/负升温系数协同效应的研究

采用乳液聚合的方法,利用Fox方程进行设计合成了玻璃化温度可控型聚(甲基丙烯酸甲酯-丙烯酸丁酯)[P(MMA-BA)]。借助激光粒度分布仪得到了控制乳液的粒径分布与大小的工艺条件;利用差热扫描量热仪(DSC)测定了聚合物的玻璃化温度(Tg)。实验发现所测的Tg与实验设计值有一定的偏差,为此对Fox公式进行了适用性的修正,理论设计和实测结果达到了很好的吻合。重点探讨了丙烯酸粘结料树脂玻璃化温度与导电填料的配比对电热膜电阻值稳定性的影响。利用扫描电子显微镜观察分析导电网络。结果表明,非晶态丙烯酸高聚物的PTC效应显著,消除了导电填料在温度升高过程中的NTC效应。

石墨烯电热窗帘的制备及性能研究

将无水乙醇作为溶剂,以石墨烯作为填充材料,调配出石墨烯基导电油墨,再印刷出石墨烯电热膜,制备出石墨烯电热窗帘成品。实验结果表明,石墨烯电热窗帘具有良好的热稳定性能,其升温速度快,瞬时温度高,热响应时长短,温度分布均匀性良好,其发散出的远红外线能够充分被人体吸收,可以达到促进新陈代谢、美容养颜的保健作用。未来,石墨烯在各个领域都将具有重要的应用前景。

Solid-state yet flexible supercapacitors made by inkjet-printing hybrid ink of carbon quantum dots/graphene oxide platelets on paper

Paper-based flexible supercapacitors(SCs) show advantages due to the improved adhesion between paper and active materials, the simplified printing process and the lower cost, compared to other substrates such as plastics. Here we report the fabrication of solid-state yet flexible SCs by inkjetprinting a hybrid ink consisting of carbon quantum dots(CQDs) and graphene oxide(GO) platelets, followed by casting of polyvinyl alcohol(PVA)/sulfuric acid(H2SO4) gel electrolyte. The SC obtained from 100-time-printing of the hybrid ink shows a specific capacitance of ~1.0 mF cm-2 at a scan rate of 100 mV s-1, which is enhanced by nearly 150%;the whole device including paper substrate, gel electrolyte and active material demonstrates an energy density of 0.078 mW h cm-3 at a power density of 0.28 mW cm-3. In addition, the excellent mechanical strength of GO platelets ensures the good flexibility and mechanical robustness of the printed SCs, which show a retention of 98% in capacitance after being bended for 1,000 cycles at a bending radius of 7.6 mm. This study demonstrates a promising strategy for the large-scale preparation of low-cost, lightweight, and flexible/wearable energy storage devices based on carbon-based ink and paper substrate.

CuCl_(2)-doped graphene-based screen printing conductive inks

The preparation of graphene-based conductive inks and their application in the field of flexible electronics have been extensively studied.However,improving the conductivity of the printed patterns always induces the neglect of the rheological properties of the graphene-based conductive inks or the mechanical properties of the as-printed patterns.In this study,the p-type doping of graphene with CuCl_(2)as the dopant is realized through liquid phase reaction,and the doped graphene powders are used to prepare the graphenebased conductive inks with a conductivity of 3.13×10^(4)S m^(-1).Subsequently,to simplify the preparation of inks,CuCl_(2)is directly added into the graphene-based conductive inks,achieving the p-type doped graphene ink with the conductivity of 3.64×10^(4)S m^(-1).The read range of ultrahigh-frequency radio frequency identification antenna and the temperature of the flexible electrothermal film printed with the CuCl_(2)-doped graphene-based conductive inks can reach 7.15 m and 200℃,respectively when the equivalent isotropically radiated power is equal to 4 W and the input power density is 0.94 W cm^(-2).Moreover,good rheological properties of the conductive inks and high mechanical properties of the printed patterns are also obtained.