The manuscript "Focused Ion Beam-Fabricated High-Performance Nickel-Ruthenium Nano-Supercapacitor" presents a good advancement in the miniaturization of supercapacitors for portable and wearable electronics. The study successfully demonstrates the fabrication of a nano-supercapacitor using focused ion beam technology, featuring interdigitated electrodes with extremely small spacings and a thin NiRu/RuO2 coating. The device exhibits excellent electrochemical performance, including high areal capacitance, low equivalent series resistance, and high power density. The practical applicability is underscored by its effective use as an AC line filter. Overall, this work reports a promising device for energy storage and power conditioning in microscale devices.

1. Please provide more detail on how your FIB fabrication approach differs from previous works. Specifically, I would like to understand the innovations or modifications you implemented to overcome challenges and achieve superior electrochemical performance in your nano-supercapacitors. Highlighting the current limitations and challenges faced by existing nano- and micro-scale supercapacitors would underscore the novelty and necessity of your approach.

2. It would be beneficial if you could include a photograph of your fabricated device. Visualizing the structure and design would aid in comprehending your experimental setup.

3. While the practical applications of the nano-supercapacitor, such as in AC line filtering, are well-discussed, I recommend including a more detailed discussion on the long-term stability and potential degradation mechanisms of the device.

4. The title might not fully capture the fabrication process described. Considering the involvement of both electrodeposition and focused ion beam patterning, it may be more accurate to reflect this dual approach in the title to clarify your methodology.

5. To better contextualize the performance improvements, I suggest including comparative data or references to previous works. For instance, a table summarizing key performance metrics alongside those of comparable devices from the literature would enhance clarity.

6. The manuscript mentions both aqueous and non-aqueous devices. Providing a detailed experimental method for the fabrication with the non-aqueous electrolyte would be useful. Additionally, the term "non-aqueous electrolyte" might not be accurate, it is still water-based; it seems more like a polymer electrolyte.

would suggest adjusting the horizontal axis of Fig. S6. The title of the horizontal axis appears too close to the axis itself.