A stratagem is implemented to widen the potential window in aqueous supercapacitors beyond the 1.23 V restrictions. The widening of the potential window is accomplished by a heterojunction design combining both negative and positive redox potential material. For the positive potential, VO(OH)₂ is employed and intentionally synthesized with a nanorod morphology to transform the battery's mechanistic behavior into extrinsic pseudocapacitive behaviour. Then, a VO(OH)₂ heterojunction is designed with low-cost activated carbon (HAC) derived from sustainable plant waste (hemp stem), which works in a negative potential window. The designed heterojunction not only harvested a large energy density (149.31 W h kg⁻¹ @ 1468.6 W kg⁻¹) in a symmetric cell, but also achieved a large voltage of 1.5 V. Here HAC, in addition to widening the potential window, also supports the VO(OH)₂ nanorods by preventing them from dissolution. The stabilization of the VO(OH)₂ phase was displayed in the attainment of a high rate capability (82.6% capacitance retention) upon a 5-fold current density increase. Supplementary to this, a stable cycling performance is also evaluated (96%, 10 000 cycle), which again precludes any doubt about the dissolution of VO(OH)₂. This work offers a distinctive approach and can also be applied to other charge storage materials to remove the 1.23 V limitation.

中文翻译：

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VO（OH）2纳米棒的异质结到大麻茎衍生的碳上，用于高压（1.5 V）对称超级电容器

采取了战略措施，以扩大水性超级电容器的潜在窗口，使其超过1.23 V的限制。电位窗口的加宽是通过异质结设计实现的，该异质结设计将负和正氧化还原电势材料结合在一起。对于正电势，采用VO（OH）₂并有意地以纳米棒形态合成，以将电池的机械行为转变为外在的假电容行为。然后，使用源自可持续植物废料（大麻茎）的低成本活性炭（HAC）设计VO（OH）₂异质结，该活性炭在负电位窗口中工作。设计的异质结不仅收获了大的能量密度（149.31 W h kg ^-1 @ 1468.6 W kg ^-1），但也达到了1.5 V的大电压。在这里，HAC除了扩大电位窗口外，还通过防止VO（OH）₂纳米棒溶解来支持它们。VO（OH）₂相的稳定表现为在电流密度增加5倍时达到高倍率能力（82.6％的电容保持率）。作为补充，还评估了稳定的循环性能（96％，10000个循环），这再次消除了对VO（OH）₂溶解的怀疑。这项工作提供了一种独特的方法，也可以应用于其他电荷存储材料以消除1.23 V的限制。