兩相混合二氧化錳/含氮石墨烯複合材料應用於可撓式非對稱固態超級電容器

Application of Mixed-Phase MnO2/N-Containing Graphene Composites to Flexible Asymmetric Solid-State supercapacitors

邱欣雅(Hsin-Ya Chiu)

指導教授 ： 卓君珮

國立暨南國際大學/科技學院/應用材料及光電工程學系/碩士(2018年)

摘要

本研究透過低成本、簡易的水熱法合成超級電容器之電極活性材料。以含氮石墨烯做為基底層，在其上生長α-和γ-兩相混合之二氧化錳，並調整錳含量的比例，製備出條狀結構之含氮石墨烯/二氧化錳複合物(x-NGM)。製作元件時，採用PVA/LiCl電解質凝膠膜作為兩電極之分隔層，進而探討電容特性。研究結果表明過高的錳含量不利於離子傳輸和法拉第電荷轉移，其電容特性隨之下降。同時發現過多的質量負載亦會使導電率下降，進而影響超級電容器的電容特性。3-NGM1//G1元件經CV曲線計算，可獲得高達579 F·g-1之比電容。以GCD法在1 A·g-1的電流密度下進行測試，其最高能量密度和功率密度分別為73.6 Wh·kg-1和4400.0 W·kg-1，說明了其具備快速充放電能力，且提供最大的充電容量。為鑑定元件之循環穩定性，採GCD法在1 A·g-1的電流密度下，經2000次的彎曲循環後，其比電容的維持率約86.71 %。本研究之可撓式固態非對稱超級電容器具高度靈活性、循環穩定性，和良好的電容性能，可歸因於兩相混合二氧化錳和含氮石墨烯的協同效應。擬電容材料搭配電雙層電容材料的快速充放電特性，結合兩種電荷儲存機制，有助於提升電荷傳輸、降低電荷轉移阻抗，進而改善電容特性。

關鍵字

含氮石墨烯 ； 二氧化錳 ； 電極活性材料 ； 超級電容器 ； 可撓式非對稱固態超級電容器

並列摘要

In this study, the electrode active materials of supercapacitors were prepared by a low-cost facile hydrothermal approach. The N-containing graphene/MnO2 composites (x-NGM) were obtained by growing α- and γ-phase MnO2 nanostructures on the surface of N-containing graphene. A PVA/LiCl electrolyte gel membrane was employed as the separator between two electrodes for supercapacitors. By changing the content of Mn and adjusting the mass loading of active materials, the capacitance characteristics of various electrodes and devices were investigated. Excessive Mn contents were proven to be detrimental to ion transport and faradaic charge transfer, and inferior capacitance characteristics were thereby resulted. Too much mass loading was also demonstrated to decrease conductivity, leading to worse capacitor performance. After calculation by CV results, the 3-NGM1//G1 device exhibited the highest specific capacitance of 579 F·g-1. The corresponding energy and power densities were 73.6 Wh·kg-1 and 4400.0 W·kg-1, respectively, implying its rapid charge/discharge capacity. After 2000 bending cycles under the current density of 1 A·g-1 by GCD method, the retention rate of specific capacitance was found to be around 86.71 %. The high flexibility, cycling stability, and good capacitance properties could be attributed to the synergistic effect of mixed-phase MnO2 and N-containing graphene. By combining the electric double-layer material with pseudo-capacitance materials, the two charge storage mechanisms were joint to improve charge transfer, conductivity, and thus capacitor performance.

並列關鍵字

N-containing graphene ； manganese dioxide ； electrode active materials ； supercapacitors ； flexible asymmetric solid-state supercapacitors

參考文獻

參考文獻

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