Holey graphene/MnO2 nanosheets with open ion channels for high‐performance solid‐state asymmetric supercapacitors,International Journal of Energy Research

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Holey graphene/MnO2 nanosheets with open ion channels for high‐performance solid‐state asymmetric supercapacitors
International Journal of Energy Research ( IF 4.3 ) Pub Date : 2020-01-27 , DOI: 10.1002/er.4976
Xia Li ₁ , Aimei Gao _{1,

2} , Dong Shu _{1,

2,

3} , Kemeng Yang ₁ , Xiaoping Zhou ₁ , Zhenhua Zhu ₁ , Fenyun Yi _{1,

2} , Ronghua Zeng _{1,

3}

Affiliation

Holey graphene/MnO₂ (HG/MnO₂) composites with open ion channels are synthesized by an electrostatic self‐assembly method. The HG with rich in‐plane nanopores is prepared via a mild etching reaction first, followed by modified with poly‐diallyldimethylammoniumchloride (PDDA) to transfer the surface charge of HG nanosheets from negative to positive, which are eventually assembled on the negatively charged MnO₂ nanosheets via electrostatic attraction. As a result, the HG allows ions to pass through the graphene sheet, improving the ion transport channels. Besides, the electrostatic self‐assembly between HG and MnO₂ enables the composite a high conductivity, providing effective electron transport pathways. The HG and MnO₂ sheets are observed to be tightly bounded by the transmission electron microscope (TEM), and the HG content in the composites is determined to be 9.6% to 20% by the thermogravimetric (TG) test. The HG/MnO₂‐2 electrode with the HG content of around 14.8% displays the large specific capacitance of 219.3 F g⁻¹ at 0.5 A g⁻¹ and the high rate capacity of 134.7 F g⁻¹ at 10 A g⁻¹. Furthermore, the as‐prepared solid‐state asymmetric supercapacitors (SSAS) achieve a wide stable operating voltage of 1.8 V, a high energy density of 16.8 Wh kg⁻¹ at the power density of 224.6 W kg⁻¹, and low capacitance degradation of only 6.3% after 5000 cycles.

中文翻译：

具有开放离子通道的多孔石墨烯/ MnO2纳米片，用于高性能固态非对称超级电容器

通过静电自组装方法合成具有开放离子通道的多孔石墨烯/ MnO ₂（HG / MnO ₂）复合材料。首先通过温和的刻蚀反应制备具有丰富的平面纳米孔的HG，然后用聚二烯丙基二甲基氯化铵（PDDA）进行改性，将HG纳米片的表面电荷从负转移到正，然后将其组装在带负电荷的MnO _2上。纳米片通过静电吸引。结果，HG允许离子通过石墨烯片，从而改善了离子传输通道。此外，HG和MnO ₂之间的静电自组装使复合材料具有高导电性，并提供有效的电子传输路径。HG和MnO ₂通过透射电子显微镜（TEM）观察到薄片紧密结合，并且通过热重（TG）测试确定复合材料中的HG含量为9.6％至20％。HG / MnO ₂ -2电极的HG含量约为14.8％，在0.5 A g ^-1时显示219.3 F g ^-1的大比电容，在10 A g ^-1时显示134.7 F g ^-1的高倍率容量。此外，所制备的固态非对称超电容器（SSAS）达到1.8 V的宽稳定的工作电压，16.8瓦公斤高能量密度^-1处的224.6的功率密度钨千克^-1，和低容量退化5000次循环后仅6.3％。

更新日期：2020-01-27

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