In this work, a novel strategy of high-temperature oxidation-activation followed by rapid low-temperature aqueous-reflux treatment is developed to prepare transition metal oxide-activated carbon (TMO-AC) composites for supercapacitor applications. The super-absorbent polymer is selected as the carbon source, and the highly oxidative potassium salts KFeO/KMnO serve as both precursors for TMO and activators for AC. AC possesses a well-developed porous structure. Moreover, TMO grows uniformly in-situ on AC surface and displays a small size below 10 nm. The prepared FeO-AC and MnO-AC composites exhibit remarkable specific capacitance of 645.0 and 548.0 F g, respectively. Hybrid aqueous supercapacitors are assembled with FeO-AC and MnO-AC as negative and positive electrodes, respectively. A stable operating voltage of 1.2 V is achieved in the KOH electrolyte, resulting in a remarkable 90.2% capacitance retention over 10,000 cycles. Furthermore, in the NaSO electrolyte, a wide 1.6 V voltage window is obtained, contributing to a substantial energy density of 49.35 Wh kg. This work provides an interesting approach for the fabrication of high-performance TMO-carbon composite electrodes.

中文翻译：

---

双功能高氧化钾盐为混合水系超级电容器提供高性能过渡金属氧化物/活性炭

在这项工作中，开发了一种高温氧化活化随后快速低温水回流处理的新策略，以制备用于超级电容器应用的过渡金属氧化物-活性炭（TMO-AC）复合材料。选择高吸水性聚合物作为碳源，高氧化性钾盐KFeO/KMnO既作为TMO的前体，又作为AC的活化剂。 AC 具有发达的多孔结构。此外，TMO在AC表面上均匀地原位生长，并且显示出小于10 nm的小尺寸。制备的 FeO-AC 和 MnO-AC 复合材料分别表现出显着的比电容，分别为 645.0 F g 和 548.0 F g。混合水系超级电容器分别以 Fe3O-AC 和 MnO-AC 作为负极和正极组装而成。 KOH 电解液可实现 1.2 V 的稳定工作电压，在 10,000 次循环后电容保持率高达 90.2%。此外，在 NaSO 电解质中，获得了 1.6 V 的宽电压窗口，从而实现了 49.35 Wh kg 的能量密度。这项工作为高性能 TMO-碳复合电极的制造提供了一种有趣的方法。