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⁻² and 158 mF cm⁻², respectively. The measured areal capacitance of the assembled symmetrical supercapacitors was 93.6 mF cm⁻², and the areal energy density reached 33 μW h cm⁻² at a power density of 793 μW cm⁻². 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.

中文翻译：

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通过引入氧官能团提高碳材料作为双极电极的电化学性能

碳材料在储能装置中常被用作正负极（双极电极材料），显着降低了电极的制备复杂度。在此，安装在碳布 (CCC) 上的氧改性碳纳米管在安全的中性电解质中作为正电极和负电极呈现出高面积电容。氧官能团的引入有利于形成许多电化学活性位点和有利于离子扩散的缺陷。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）。而当用作正极时，电荷存储特性来自多缺陷碳材料中电解质离子的嵌入和脱嵌。在正极和负极测得的最大面电容为 336 mF cm^-2和 158 mF cm ^-2分别。组装后的对称超级电容器的实测面积电容为93.6 mF cm ^{-2 ，在793 μW cm -2}的功率密度下，面积能量密度达到33 μW h cm ^-2。相信该工作阐明的有效制备方法和电化学机理可以指导碳布在超级电容器中的实际应用。