Q2. How can the peak height of graphite be considered proportional to the crystal size?
The peak height of XRD can be considered proportional to the crystal size, e.g. (0 0 2) peak height is proportional to Lc and (1 0 0) peak height is proportional to La.
Q3. What is the effect of the thermal energy on the stacking of graphene sheets?
During the activation processes of sample preparation, thermal energy may be sufficient to break the links between adjacent graphene sheets, allowing some to rotate into parallel orientation.
Q4. What is the key to making the activated carbons with high specific capacitance?
choosing precursors and proper carbonization and activation processes, which can result of lower La value, would be the key of making the activated carbons with high specific capacitance.
Q5. Why is it unlikely that functional groups can be chemically bonded to its surface?
Because there are no unsatisfied chemical bonds or free electrons, it is unlikely for functional groups to be chemically bonded to its surface, except to the defect sites with high strains.
Q6. What is the reason for the low capacitance obtained from the basal plane?
the low capacitance obtained from the basal plane is attributed to its semiconducting properties, the higher capacitance for the edge layer is at least partially attributed to the contribution of the functional groups on the surface.
Q7. What is the role of surface groups in the electrochemical performance of a supercapacit?
Understanding the electrochemical performance of thematerials over different potential ranges is key to the selection of positive electrode materials and negative electrode materials for ‘‘non-symmetric’’ supercapacitor systems.
Q8. What is the effect of bias potential on the basal graphite?
In addition, bias potential on the basal graphite mainly changes the potential of the space charge region and has little impact on the potential in the Helmholtz layer.
Q9. What is the effect of surfactant on the surface of an activated carbon electrode?
The nontreated activated carbon electrode floats on the surface of KOH electrolyte; the same electrode, treated with the surfactant absorbs the electrolyte and sinks to the bottom of the container, gas bubbles can be seen rising from the electrode.
Q10. What was the main contributor to the overall impedance?
at high frequency range, rather than the double-layer, Faradaic reaction of the organic surfactant was the major contributor to the overall impedance, since only small portions of the electrode surface area was accessed in the frequency range.
Q11. How can the authors estimate the lateral extent of graphene layers?
The lateral extent of the graphene layers (La) can be estimated from the width of (1 1 0) and (1 0 0) X-ray diffraction (XRD) peaks while the stacking number of graphene sheets (Lc, or N) can be estimated through the width of (0 0 2) peak.
Q12. What is the reason for the porous structure of the electrodes?
the same porous structure makes the electrodes more complex, not only due to the kinetics of electrochemical accessibility to the micropores [15], but also owing to the presence of various surface functional groups.
Q13. What is the lateral extent of the graphene sheets?
in that instance, an activated carbon can be treated as the combination of a lot of small domains that consist of a few graphene sheets in parallel.
Q14. What was the X-ray powder diffraction pattern of each sample?
The X-ray powder diffraction pattern of each sample was collected using a Siemens D5000 powder diffractometer equipped with a Cu target X-ray tube and monochrometer.
Q15. How many years ago did the concept of storing relatively high electrical energy in relatively small capacitors?
Although the concept of storing relatively high electrical energy in reasonably small capacitors was proposed about three decades ago [8], the real efforts of research anddevelopment toward practical commercialization only happened over the past 10 years.