纳米SiO2填料对离子凝胶电解质及高压超级电容器性能的影响

Effects of SiO2 nanoparticle fillers on the performances of ionogel electrolyte and high voltage supercapacitors

以SiO2纳米颗粒为填料,通过溶液浇筑法合成了纳米复合离子凝胶电解质,研究了SiO2填料对离子输运的影响规律。基于离子凝胶电解质构筑了准固态电容器,探讨了无机填料对电容器性能的影响,以活性炭为电极、凝胶电解质为隔膜,构筑了准固态双电层电容器。结果表明,SiO2的加入没有改变隔膜电解质的微观形貌,但有效改善了浸润性,提高了离子电导率。高SiO2添加量的隔膜电解质电化学性能更优,当添加8wt%SiO2时凝胶电解质电化学性能最优。SiO2的加入可有效提高活性炭准固态电容器的性能,电容器的比容提升约15%,经4000次循环后容量保持可达100%。电解质高温稳定性良好,器件最高使用温度可达60℃。基于该复合电解质构筑的电容器具有良好的高温性能,电容器比容随温度升高而逐渐提升,60℃时能量密度可达81.36 Wh/kg。

Quasi-solid capacitor composed of polymer gel electrolytes are thinner, lighter, cheaper, and more flexible. They can be used as energy devices for wearable and portable electronic devices, and have a very broad application prospect. In this work, the ionogel electrolyte separator was constructed by a simple solution casting method with silicon dioxide nanoparticles as filler. The effects of silicon dioxide nanoparticles on the ion transport were exploited. Based on the ionogel electrolyte separator, a quasi-solid capacitor was constructed, andthe influence of silicon dioxide nanoparticles on the performance of the capacitor was evaluated. The electrolytes with different amounts of silicon dioxide were studied. The results showed that the addition of silicon dioxide did not change the microscopic morphology of the ionogel electrolyte, but it effectively improved the wettability and the ionic conductivity of the electrolyte. The electrochemical performance of the electrolyte with high silicon dioxide addition was more beneficial. The electrolyte exhibited the most excellent ionic conductivity when 8 wt% silicon dioxide was added. Quasi-solid electric double layer capacitors were assembled using activated carbon as the electrodes and ionogel electrolyte as the separator. Because silica dioxide effectively promoted ionic conductivity and reduced electrolyte internal resistance, the addition of silicon dioxide improved the performance of activated carbon quasi-solid capacitor effectively, the specific capacitance increased nearly 15%. After 4 000 cycles, the device’s specific capacity was maintained at 100%. Due to the excellent high temperature stability of the electrolyte, the quasi-solid capacitor maximum operating temperature up to 60 ℃. The specific capacitance of the device gradually increased with increasing temperature, and the energy density reached 81.36 Wh/kg at 60 ℃. This work provided an effective guidance for constructing a complex ionogel electrolyte-based quasi-solid supercapacitor.