The material performance is greatly dependent on the mass loading and significantly declines in highly loaded electrodes. It is misleading to take advantage of the high capacity by a low active material mass loading to compare with the commercial device, which generally has a high mass loading on the order of ∼10 mg cm−2. The authors may take a look at the following references:

[1] Y. Gogotsi, P. Simon, True Performance Metrics in Electrochemical Enrgy Storage, Science  334 (2011) 917–918.

[2] H. Wang, C.M.B. Holt, Z. Li, X. Tan, B.S. Amirkhiz, Z. Xu, et al., Graphene – Nickel Cobaltite Nanocomposite Asymmetrical Supercapacitor with Commercial Level Mass Loading, Nano Res. 5 (2012) 605–617.

[3] Jaime.S. Sanchez, A. Pendashteh, J. Palma, M. Anderson, R. Marcilla, Anchored Fe3O4 Nanoparticles on rGO Nanosheets as High-Power Negative Electrodes for Aqueous Batteries, ChemElectroChem. 4 (2017) 1295–1305.

The mass loading in supercapacitor testing is very important. If mass loading is low the results are not reliable. Typically, it should be between 1 to 10 mg/cm2. But if you are using glassy carbon for depositing nanomaterials then such high loading is not possible. But with nickel foam it can be achieved.

Best wishes

The material performance is greatly dependent on the mass loading and significantly declines in highly loaded electrodes. It is misleading to take advantage of the high capacity by a low active material mass loading to compare with the commercial device, which generally has a high mass loading on the order of ∼10 mg cm−2. The authors may take a look at the following references:

[1] Y. Gogotsi, P. Simon, True Performance Metrics in Electrochemical Enrgy Storage, Science  334 (2011) 917–918.

[2] H. Wang, C.M.B. Holt, Z. Li, X. Tan, B.S. Amirkhiz, Z. Xu, et al., Graphene – Nickel Cobaltite Nanocomposite Asymmetrical Supercapacitor with Commercial Level Mass Loading, Nano Res. 5 (2012) 605–617.

[3] Jaime.S. Sanchez, A. Pendashteh, J. Palma, M. Anderson, R. Marcilla, Anchored Fe3O4 Nanoparticles on rGO Nanosheets as High-Power Negative Electrodes for Aqueous Batteries, ChemElectroChem. 4 (2017) 1295–1305.

hello Pramod K Kalambate

Its not possible to use nickel foam or other matrix materials for depositing nanoparticles keeping various applications in mind. So, then whats the remedy?

And I want to know what are the other disadvantages of low mass loading. I guess only reliability. Any other factors?

Dear Jaime S. Sanchez

First of all thanks for suggesting excellent papers. In the nanomatrials thin film, we can't even control the mass loading aspect. practically, it is very low as well. then whats the remedy??

In another example, as is reported by Yang et al. [1] the specific capacitance of MnO2 thin films decreased from 203 to 155 F g−1 when the mass loading increased from 6 to 18 mg cm−2. However, a high mass loading is needed for high power and energy density, which thus makes the application of a light and durable supercapacitor possible.

So, the remedy should be a compromise between the performance of your material in a three electrode configuration and the energy density and power density they are able to develop in your final device.

[1] Yang, J., et al., Nanostructured porous MnO2 on Ni foam substrate with a high mass loading via a CV electrodeposition route for supercapacitor application. Electrochimica Acta, 2014. 136: p. 189–194.

Dear Karthik Bhat

I agree with your answer. But the problem is 0.5 mg/cm2 can not be assumed as high mass loading. We can have exact same amount of mass loading for nanostructured materials towards supercapacitor application. Even some of the reviewers asked that such small mass loading is not trustworthy as well. They asked for more than 1 or 2 mg/cm2 even 5 mg/cm2 as considerable and reliable active electrode mass.

Hi Bidhan,

For materials evaluation, you would prefer using a low loading since you want to know the intrinsic electrochemical property of your material, which will only take place homogeneously at low thickness electrodes.

As you increase loading, electrode thickness increases and then you will have mass transfer problems across the thickness due to limited ionic conductivity as well as increased ohmic resistance (voltage drop) due to electronic conductivity issues .

Those reasons make performance poorer with increasing loading, but in practical devices we need high loadings to reach significants levels of energy and power density. Otherwise the weight of the current collectors and electrolyte (inert from an electrochemical point of view) is too high in comparison with the weight of the active materials, so cell characteristics are inappropriate.

Dear Jaime S. Sanchez

Thanks for your answers. I'll do the same as you can check my publications too. Sometimes you can't increase mass loading to a certain level. after some times, the film will be peeled off. So, have to go for the less mass loading for electrode.

Hello Sergio Mollá,

But sometimes the mass loading is not in our hand. Actually whether using chemical method to deposit thin films, we can't increase the mass loading as per our choice. after certain time, the film will peel of from the substrate. And another issue is also there as you've mentioned in your answer.

And I've no preference at all. I'm searching a reliable way to deal with actually. sometimes reviewers reject the paper only considering about low mass loading.

I agree with Sanchez

Dear Bidhan,

Yes you are right that we can't control the mass loading while using Chemical methods to deposit thin films. Major controlling factors in chemical methods are deposition time, concentration, etc and they are sometimes not much effective for mass control. This problem can be efficiently solved by using printing techniques for material deposition. We can have a better control over mass loading and thickness of the material using printing process. I hope the following publication will be helpful to overcome this problem:

Article Inkjet-Printed Electrodes on A4 Paper Substrates for Low-Cos...

I feel that low mass loading is preferred for thin film and large area super-capacitor electrodes (where areal capacitance is generally preferred). Otherwise an optimum mass loading is required for the practical super-capacitors.

Hello Poonam,

First of all congrats for your recent success in ACS Appl. Mater. Interfaces.

For chemical methods such as CBD, SILAR, electrodeposition; its hard to control mass as here we get material in thin film form directly. Other methods (such as hydrothermal) it is easier to control mass loading as here thin film is prepared using binder. So, here we can increase mass loading to a certain level. And its better to from large area deposition and calculate areal capacitance to overlook the situation. I've done the same in my previous publication attached below.

link- Article Large scale flexible solid state symmetric supercapacitor th...

Thanks Bidhan!

Nice article. Yes the mass loading control is really complex while using the chemical methods. Other material deposition technique can really solve the problem.

Hi....

I think this is one of the most important question I have come across here at ResearchGate.

Kindly go through stoller's and Ruoff papers...they gave systematically summarized the best practice method for the determination of supercapacitor performance of a material.

Recently, I also witnessed a massive change in the specific capacitance while performing experiments at very low mass loading. I found that up to 2-3 increments, specific capacitance increased but beyond a particular mass loading, it started giving voltage plateau, which we know is highly undesirable. Surprisingly, other factors like rate performance and cycle life were significantly different in each case...

Yes Mohit Saraf,

So, we have to go for optimum relationship for mass loading and capacitance value. Too much mass loading causes bulk formation, repeals the nano kinetics between inner and outer layer of film.

Hybrid supercapacitor mass balance equation?

Please Anyone help for Mass balance equations for Battery type hybrid supercapacitor electrodes1:2 ratio and 1:4 ratio calculation .

There is NO, any, general rule.

We have, always, to test for an optimum relationship for mass loading and capacitance value for each specific case (class) of the: 1) mass loading method (technique) and the 2) morphological details of the (active mass) particles. Notably, these complex morphologies can be classified under the:

1) microscopic skeleton of the principal geometric dimensionality[1] (0D, 1D, 2D and 3D) of the (active mass) particles,

in combination with the

2) mesoscopic and microscopic (modeling of the) transport physics[2] of the (main, active) charge carriers, both electronic and ionic.

Also, the choice of the substrate (current collector) increases the complexity for an optimum relationship (of the mass loading vs capacitance value) due to some, additional, issues related with thermodynamic[3] and kinetic[3] limitations.

1. Chapter 13: Functional Nanomaterials (2D, 1D, and 0D) http://www.physics.uwo.ca/~lgonchar/courses/p2800/Chapter13_FunctionalNanowires.pdf

2. The transport physics can be revealed by EIS measurements and the following (EIS-) modeling.

3. Safe potential window of the electrodes' interfaces (to avoid electrolysis), that can be evidenced by EIS.

4. Full surface electrodes' surface coverage, in order to avoid any (LOW value for a) parallel (to C) R in our SC cell, that can be, also, evidenced by EIS.

If you want to find the intrinsic capacitance of your active material at the electrode, then you should try to use a low loading. Since tapped density of the electrode depends on the nature and particle size of your active material, I would suggest to use a loading equivalent to a final thickness around 50-60 microns.

From 1-5 mg for single electrode is OK

Article Superior supercapacitive performance in porous nanocarbons

Hi Thirumal Vediyappan

The issue is very common whenever considering asymmetric device. Mainly, asymmetric device made of one pseudocapacitive material (high capacitance) and one EDLC material (low capacitance). Precise mass loading is essential. Otherwise you can't find a stable and high-performance asymmetric device i.e, device with asymmetric cathodic and anodic currents, low Coulombic efficiency, low capacitive retention during cycling etc. Sometimes, the difference between the capacitances of positive and negative electrodes is so diverse that its hard to even balance.

You can also increase mass loading to a certain limit. Again, increasing mass loading not always associates with high capacitance. sometimes, electrochemical reaction kinetics slows down with excess mass loading.

You don't need to exact balance the mass loading but you just need to optimize as much as you for high performance via optimizing the factors and parameters.

Ioannis Samaras already described it in comments.

The pdf Ioannis Samaras atatched is really very help helpful.

Additionally, the influence of electrolyte on electrochemical system i.e, electrodes, separator and other the passive components is considerable too. The pH can also be critical in terms of electrode stability, and corrosion.

Along with, plz go through the following articles.

Article Electrode Mass Balancing as an Inexpensive and Simple Method...

https://www.nature.com/articles/ncomms14264

Hi Bidhan, How are you recently ?

I am interested in this question you propose. Because here is the same question as in film electrode battery. In my perspective, performance of material, or mass loading are two aspects of material properties. Low mass loading (0.1 ~1.0mg/cm2) or high mass loading (~60 mg/cm2) are two topics, former is about acedemic thinking, and later one for application (industrial/ engineering thinking). For new material, start from low mass loding (with suitable active mass percentage) can help us understand more about target material. In case of High mass loading (the same time high active mass percentage), adhension of electrode, conductivity problem may be emerged that would lead to converse properties of the materials. So maybe try low mass loading with high high active mass percentage is better I think. With more time, more formulations study could be researched.

Hi Yawen He

Hope you are doing well too.

Your answer is informative and well explained. We always try to optimze the electrode performance with mass loading. Very low mass loading means less reliability of results. So, we have to check couple of set of analysis with high and low mass loading as well to see the variation. It will give you a point of discussion and you will find your own answer. Thats the best way, I guess.

The high mass loading may inhibit the intercalation of electrolyte ions into inner active sites of the electrodes resulting the poor electrochemical performance. So, efficient negative electrode material is needed to overcome these issues.

Hello i want to do electrochemical analysis of supercapacitors, can any one reccomend me simple method which i can repeat and reproduce the data.