In this work, we have optimized and fabricated pristine molybdenum dioxide (MoO) electrodes over the Silicon (Si) substrate and examined the impact of various ion-loaded aqueous electrolytes on their electrochemical behavior. The sputtered electrodes exhibited a high crystalline structure and a very low resistivity. These highly conductive electrodes were tested in three different aqueous electrolytes (acidic, neutral, and alkaline) to establish a relation between the electrode and the nature of the electrolyte to achieve optimal electrochemical performance and cyclability. The electrochemical kinetics showed that the charge storage mechanism was unique for all the electrolytes. The capacitive current was dominant in the neutral electrolyte, whereas it was diffusive dominant in alkaline and 70 % capacitive in the acidic electrolyte. Our findings indicated that the MoO@Si electrode exhibited superior electrochemical activity in an acidic electrolyte. The electrode showed a voltage window of 0.6 V with an areal capacity of 24 mF/cm at 0.1 V/s scan rate. Moreover, the electrode also demonstrated excellent cyclability and capacitance retention (∼145 %) till 5000 cycles. These results highlighted that the binder-free MoO@Si electrode showed outstanding electrochemical activity and stability, which makes it suitable for sulfuric acid electrolyte-based energy storage systems.

中文翻译：

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溅射沉积结晶 MoO2 薄膜作为超级电容器的高容量且稳定的电极材料：机械/电化学见解

在这项工作中，我们在硅 (Si) 基板上优化并制造了原始二氧化钼 (MoO) 电极，并研究了各种离子负载水性电解质对其电化学行为的影响。溅射电极表现出高晶体结构和非常低的电阻率。这些高导电性电极在三种不同的水性电解质（酸性、中性和碱性）中进行了测试，以建立电极和电解质性质之间的关系，从而实现最佳的电化学性能和可循环性。电化学动力学表明，所有电解质的电荷存储机制都是独特的。中性电解液中电容电流占主导地位，而碱性电解液中电容电流占主导地位，酸性电解液中电容电流占70%。我们的研究结果表明，MoO@Si 电极在酸性电解质中表现出优异的电化学活性。该电极在 0.1 V/s 扫描速率下显示出 0.6 V 的电压窗口和 24 mF/cm 的面积容量。此外，该电极在 5000 次循环之前还表现出优异的循环性能和电容保持率 (∼145%)。这些结果表明，无粘合剂MoO@Si电极表现出出色的电化学活性和稳定性，这使其适用于基于硫酸电解质的储能系统。