Q2. What have the authors stated for future works in "Mxene electrochemical microsupercapacitor integrated with triboelectric nanogenerator as a wearable self-charging power unit" ?
Their strategy shows that MXene microsupercapacitors are versatile and can be integrated with energy harvesting devices, which opens new possibilities in wearable/implantable sensor networks.
Q3. What is the effect of the chemically cross-linked hydrogel on the MSC?
The chemically cross-linked hydrogel shows excellent elasticity and high ionic conductivity due to alarger water content absorbed in the polymer matrix that helps in fine-tuning ionic conductivity.
Q4. What are the advantages of using a microbatteries as energy storage units?
Thin-film or micro-batteries can be used as small-scale energy storage units, but they often suffer from low power density and limited cycle life.
Q5. What is the advantage of the device?
In addition, their device can have a long lifetime for continuous energy harvesting and storage, which can be useful for powering electronics without additional power sources.
Q6. What are the promising materials for MSCs?
Carbon based materials such as activated carbon [10], onion like carbon [11], carbonnanotubes (CNTs) [12] and carbide-derived carbon [13] have been explored as electrodes for MSCs.
Q7. What is the description of the MXene?
Given its 2D layered morphology, MXene is also convenient for flexible energy storage with good mechanical property and straintunability, which gives it more versatility to be integrated with other components.
Q8. What is the maximum charge transferred per cycle?
Under the short-circuit condition, the maximum charge transferred per cycle reached about 4.2 nC/cm 2 , and the peak current was about 0.13 µA/cm 2 at the working frequency of 1.3 Hz.
Q9. What is the role of the polyvinyl alcohol in the MSC?
The chemically cross-linked polyvinyl alcohol PVA/H3PO4 hydrogel not only serves as the solid-state electrolyte, but also guarantees the structural integrity and mechanical strength of the assembled device [31].
Q10. What is the design of the TENG?
A single-electrode-mode TENG based on carbon-fiber-embedded silicone was designedfor integration with the silicone-encapsulated MXene-based MSC.
Q11. How fast can the MSC be charged?
under 10 Hz, the MSC can be charged to 0.11 V within 200 seconds, which demonstrates the fast response even at high frequencies.
Q12. What is the advantage of the MSC device?
Since the device was fabricated on flexible substrates, it can be repeatedly bent at various angles and frequencies (Fig. 1(h)) without compromising performance.
Q13. What are the advantages of using a Meyer coating?
MXene-based MSCs fabricated by employing a Meyer coating and spray-coating methods followed by a direct laser cutting process were reported [28,29].
Q14. What is the maximum output power of the triboelectric nanogenerator?
As a result, their microsupercapacitor delivers a capacitance of 23 mF/cm 2 with 95% capacitance retention after 10,000 charge-discharge cycles, while the triboelectric nanogenerator exhibits a maximum output power of 7.8 µW/cm 2.
Q15. What is the charging rate of the power band?
Fig. 4(c) illustrates the self-charging capability of the power band (Total capacitance ofthe series connected capacitor is 4 mF) under hand clapping (the clapping frequency is estimated to be 5 Hz) when no external load was connected.
Q16. How was the output power of the TENG connected with different external load resistance?
The output power of the TENG connected withvarious external load resistance was measured and plotted, with the maximum output power of 7.8 µW/cm 2 at a load resistance of 400 MΩ.
Q17. How is the self-discharge behavior of the supercapacitor measured?
The authors investigated the self-discharge behavior of their device via measuring the open circuit potential of the device after thoroughly charging it, and a slow self-discharge rate of 0.1 V/h is observed for the device, which is shown in Fig. 1(g).
Q18. What is the Raman spectrum of Ti3C2Tx?
As shown in Fig. S1(a), The Raman spectrum ofTi3C2Tx exhibits strong peaks at 200 and 722 cm -1 , which can be assigned to the A1g modes of Ti3C2O2; the additional peaks at 286, and 630 cm -1 can be assigned to the following vibrational modes: Eg of Ti3C2(OH)2, and Eg of Ti3C2F2, respectively. [30]
Q19. What is the optimum ionic conductivity of the MSC?
This solid-state MSC exhibits good cycling stability with a capacitance retention up to 76% and coulombic efficiency of 95% over 10k cycles as shown in Fig 1(f).
Q20. What is the disadvantage of the TENG-supercapacitor device?
One the other hand, the liquid electrolyte in conventional supercapacitors will evaporate if exposed to air, thus proper encapsulation of the supercapacitor is required, which makes the TENG-supercapacitor device bulky.