Stabilization of the electroactive redox centers on ideally polarisable conductive electrodes is a critical challenge for realizing stable, high performing pseudocapacitive energy storage devices. Here, we report a top-down, electrochemical nanostructuring route based on voltammetric cycling to stabilize β-MnO₂ on a single walled carbon nanotube (CNT) scaffold from a MnMoO₄ precursor. Such in situ nanostructuring results in controlled disintegration of an ∼8 μm almond like structure to form ∼29 nm β-MnO₂ resulting in a 59% increase in the specific surface area and a 31% increase in the porosity of the pseudocapacitive electrode. Consequently, the specific capacitance and areal capacitance increase by ∼75% and ∼40%, respectively. Such controlled, top-down nanostructuring is confirmed through binding energy changes to Mo 3d, C 1s, O 1s and Mn 2p respectively in XPS. Furthermore, Raman spectral mapping confirms the sequential nanostructuring initiating from the interface of CNTs with MnMoO₄ and proceeding outwards. Thus, the process yields the final CNT/β-MnO₂ electrode that is electrically conductive, facilitates rapid charge transfer, and has increased capacitance and longer stability. Furthermore, the charge-transfer resistance and equivalent resistance are significantly lower compared to conventional activated carbon based electrodes.

中文翻译：

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自上而下的电化学纳米结构伪电容电极，可提高比电容和循环效率†

为了实现稳定的，高性能的伪电容储能装置，电活性氧化还原中心要稳定在理想的可极化导电电极上，这是一个关键的挑战。这里，我们报告基于伏安循环自上而下，电化学纳米结构化的路线，以稳定β-MnO的₂上从MnMoO一个单壁碳纳米管（CNT）的支架₄前体。这种原位在〜8微米杏仁状结构的受控崩解纳米结构的结果，以形成〜29纳米的β-MnO的₂导致比表面积增加59％，伪电容电极的孔隙率增加31％。因此，比电容和面电容分别增加了约75％和约40％。通过在XPS中分别改变对Mo 3d，C 1s，O 1s和Mn 2p的结合能变化，可以确认这种受控的，自上而下的纳米结构。此外，拉曼光谱图证实了从CNT与MnMoO ₄的界面开始并向外进行的连续纳米结构。因此，该方法产生最终的CNT /β-MnO的₂导电的电极，有助于快速的电荷转移，并具有增加的电容和更长的稳定性。此外，与传统的基于活性炭的电极相比，电荷转移电阻和等效电阻明显更低。