Zhang Yaxiong, Liu Ying, Bai Yunfei, Liu Yupeng, Xie Erqing
Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University Lanzhou 730000 China
School of Physics and Optoelectronic Engineering, Ludong University Yantai 264025 China.
RSC Adv. 2020 Sep 24;10(58):35295-35301. doi: 10.1039/d0ra06888h. eCollection 2020 Sep 21.
Carbon materials are often used as both positive and negative electrodes (bipolar electrode materials) in energy storage devices, which significantly reduces the preparation complexity of the electrode. Herein, oxygen-modified carbon nanotubes mounted on carbon cloth (CCC) present a high areal capacitance as both positive and negative electrodes in a safe neutral electrolyte. The introduction of oxygen functional groups facilitates the formation of many electrochemical active sites and defects conducive to ion diffusion. When carbon materials are utilized as negative electrodes, the charge storage characteristics are mainly dependent on the adsorption and desorption of the ions (corresponding to the electric double layer capacitance). Whereas, when utilized as positive electrodes, the charge storage characteristics come from the intercalation and de-intercalation of the electrolyte ions in the multi-defect carbon material. The maximum areal capacitance measured at the positive electrode and negative electrode was 336 mF cm and 158 mF cm, respectively. The measured areal capacitance of the assembled symmetrical supercapacitors was 93.6 mF cm, and the areal energy density reached 33 μW h cm at a power density of 793 μW cm. It is believed that the efficient preparation method and electrochemical mechanism elucidated in this work can guide the practical applications of carbon cloth in supercapacitors.
碳材料常用于储能设备的正负极（双极电极材料），这显著降低了电极的制备复杂性。在此，负载在碳布上的氧改性碳纳米管（CCC）在安全的中性电解质中作为正负极均呈现出高面积电容。氧官能团的引入促进了许多有利于离子扩散的电化学活性位点和缺陷的形成。当碳材料用作负极时，电荷存储特性主要取决于离子的吸附和解吸（对应于双电层电容）。然而，当用作正极时，电荷存储特性来自电解质离子在多缺陷碳材料中的嵌入和脱嵌。在正极和负极测得的最大面积电容分别为336 mF/cm²和158 mF/cm²。组装的对称超级电容器测得的面积电容为93.6 mF/cm²，在功率密度为793 μW/cm²时面积能量密度达到33 μW h/cm²。相信这项工作中阐明的高效制备方法和电化学机制可以指导碳布在超级电容器中的实际应用。
