Jin Sohyun, Lee Haein, Yim Sanggyu
Department of Chemistry, Kookmin University Seoul 02707 South Korea
RSC Adv. 2019 Oct 7;9(55):31846-31852. doi: 10.1039/c9ra06066a.
The major problem of transition metal oxide (TMO)-based supercapacitors is their low specific energy ( ) due to the poor electrical conductivity of the TMO electrodes and narrow operating voltage window. To solve these limitations simultaneously, we propose asymmetric supercapacitors (ASCs) consisting of two composite TMO electrodes working in different potential ranges. Titanium dioxide (TiO) nanoparticle (NP)-incorporated iron oxide (FeO) and manganese oxide (MnO) NPs were used as electrode materials covering the negative and positive potential window, respectively. The specific capacitance ( ) of this asymmetric TiO-FeO‖TiO-MnO supercapacitor is comparable to that of the symmetric TiO-MnO‖TiO-MnO supercapacitor. However, the ASC can operate over a doubly extended voltage range, which resulted in a significant enhancement in the specific energy of the device. The value of the ASC at a specific power of 1000 W kg is 48.6 W h kg, which is 34.1 and 8.1 times, respectively, larger than that of the two symmetric devices.
基于过渡金属氧化物（TMO）的超级电容器的主要问题是其比能量较低，这是由于TMO电极的电导率较差以及工作电压窗口较窄所致。为了同时解决这些限制，我们提出了由两个在不同电位范围内工作的复合TMO电极组成的不对称超级电容器（ASC）。掺入二氧化钛（TiO₂）纳米颗粒（NP）的氧化铁（Fe₂O₃）和氧化锰（MnO₂）纳米颗粒分别用作覆盖负电位窗口和正电位窗口的电极材料。这种不对称TiO₂-Fe₂O₃‖TiO₂-MnO₂超级电容器的比电容与对称TiO₂-MnO₂‖TiO₂-MnO₂超级电容器相当。然而，该ASC可以在双倍扩展的电压范围内工作，这导致该器件的比能量显著提高。在1000 W kg⁻¹的特定功率下，该ASC的比能量值为48.6 W h kg⁻¹，分别比两个对称器件大34.1倍和8.1倍。
