高性能固态超级电容器:钴镍双金属硫化物负载的石墨烯气凝胶电极

High-performance solid-state supercapacitor based on Co-Ni bimetallic sulfide supported on graphene aerogel electrodes

  • 摘要: 固态超级电容器具有比液体电解质基的超级电容器安全性高,易于集成的优势,但它在实际应用中仍受到电极结构不稳定和高电容存储能力的限制。本文设计以三聚氰胺泡沫(MF)作为氧化石墨烯(GO)和Co2+、Ni2+离子浸渍的载体,利用MF多孔网络骨架、GO中含氧官能团负电荷与带正电金属离子产生的静电相互作用,经水热反应制得被褶皱GO包覆“类海胆状”Ni—Co前驱体负载的MF泡沫,后经碳化和硫化过程产生了纳米NiCo2S4颗粒均匀分散的多孔NiCo2S4/GM气凝胶材料。得益于NiCo2S4丰富的电化学位点、石墨烯较大比表面积和优异导电性的协同作用,加速了电解质的快速渗透,加快了OH扩散和Ni2+/Co2+离子与OH之间氧化还原反应过程中的电子/离子转移速率,使得所制备NiCo2S4/GM电极在电流密度为0.5 A∙g−1时,比电容高达2515.3 F∙g−1且具有较高的倍率和循环稳定性能性能。用KOH/聚乙烯醇凝胶电解质构建的NiCo2S4/GM//AC固态超级电容器功率密度为814.9 W∙ kg−1时能量密度可达51.6 Wh∙kg−1,循环10000次后其比电容保持率为93.5%。该研究制备的石墨烯气凝胶均匀负载纳米NiCo2S4颗粒是一种性能优异电极材料,且具有良好的实际应用前景。

     

    Abstract: Solid-state supercapacitors offer advantages such as higher safety and easier integration compared to their liquid electrolyte counterparts. However, it is still limited by the instability of the electrode structure and the limited capacitance storage capacity in practical applications. Herein, melamine foam (MF) was employed as a carrier for the impregnation of graphene oxide (GO) and Co2+, Ni2+ ions. By taking advantage of the porous network skeleton of MF, the electrostatic interaction between the positively charged metal ions and the negative charges of oxygen functional groups in GO, the "sea urchin-like" Ni-Co precursor encapsulated by GO was successfully created through a hydrothermal reaction. Following the carbonization and vulcanization processes, a porous NiCo2S4/GM aerogel loaded with uniformly dispersed NiCo2S4 nanoparticles was produced. The synergistic effect of the abundant active sites in NiCo2S4 and the large specific surface area coupled with the excellent conductivity of graphene, facilitates the rapid infiltration of electrolytes, thereby enhancing the diffusion of OH and the electron/ion transfer rate during the redox reaction between Ni2+/Co2+ ions and OH. Consequently, the as-prepared NiCo2S4/GM electrode exhibits a high specific capacitance of up to 2515.3 F·g−1 at a current density of 0.5 A·g−1, along with excellent rate and cycle stability performance. Using a KOH/PVA gel electrolyte, the NiCo2S4/GM//AC solid-state supercapacitor achieves an energy density of 51.6 Wh∙kg−1 at a power density of 814.9 W∙kg−1, with a specific capacitance retention rate of 93.5% after 10,000 cycles. Hence, the as-developed graphene aerogel loaded with uniformly dispersed nano NiCo2S4 particles is an electrode material with excellent performance and hold promising practical application prospects.

     

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