Internal Leakage Current in Supercapacitors

Internal leakage current in supercapacitors can be determined using a simple method, i.e. by monitoring the change in the open-circuit voltage over time for a fully charged supercapacitor. Dynamic leakage current can be determined from the curve recorded from the open-circuit test. Usually electrochemical machine with high input impedance is required for such test so that the circuits utilised to study the self-discharge mechanism do not influence the recorded values. Leakage current varies with voltage, so it would be useful to be able to calculate the value at various time interval during the self-discharge period. The performance and quality of the supercapacitor built depends predominantly on the ability to store charge over a long period of time. Leakage current usually caused by short circuit between plates or electrodes (especially in bipolarly-stacked supercapacitors) would quickly diminish the capability of the supercapacitor in fulfilling its function.

A lab prototype supercapacitor

An email about Electric Car

I was pleasantly surprised about a month ago when I received an email from K. Hoo about electric car in Malaysia. Firstly, I have to apologise for the late reply. I was certainly very impressed with Hoo's enthusiasm in electric car and it is certainly rare to find someone like him in Malaysia. Hoo has mentioned to me about his personal project on electric car and also his written mail to our Transport Minister with regards to Road Transport Act which currently restricts electric cars from being on Malaysian roads, i.e. vehicles allowed on the road require an engine to be fitted in them. This is interesting as I have ridden in a lead-acid battery powered car at the Nottingham Trent University before and was told by the professor from Loughborough University (who lead the research team) that they have road tax/license to drive the car on the road in the UK, but I can't recall the classification/category which it falls under. Nonetheless, I am humbled by Mr. Hoo with his effort in bringing up the matter with the Ministry of Transport in Malaysia.

I have also recently been brought to attention about the development of supercapacitors which may be able to complement/ maybe one day replace batteries being carried out at MIT. The electrodes of the supercapacitors are made of chemical vapour deposition grown carbon nanotubes and are able to store enough charge to power the engine of a car. Nonetheless, supercapacitors have also been fitted in the emergency doors for Airbus, indicating the relability of the technology. I personally am involved in a research which examines the viability of the application of supercapacitors in large-scale energy storage.

K. Hoo has recently emailed me with further details of his project which has certainly intrigued me further to have a closer look at his project. I do feel very privilege to be given this chance to have a good peek into his prized research. We lacked people like Hoo in Malaysia. If only we have more local scientists who dare to experiment and with a committed support from the government in terms of monetary needs etc. we would have been so much more advanced by now. For the approval of the government with regards to electric cars, I believe the first attempt would be to collaborate with local universities or research institutes. This would ensure the government's seal of approval to work on the project. Besides that, there might also be some opportunity of funding from the Ministry of Science, Technology and Innovations, which would in turn support the preliminary testings/test drive of the electric vehicle at closed circuits with available safety precautions.

In all, I would want to take this opportunity to thank K. Hoo for his emails and his discussions on the acts which restrict electric cars from being able to be driven on our Malaysian roads. I believe that we lacked innovative people like Mr. Hoo and I will always look forward to future emails from him or anyone with regards to supercapacitors, renewable energy, and green powered vehicles. We have a responsibility towards the future generation, that is to reduce carbon footprints on earth while we still can before it is too late.

Electric Car in Malaysia

Fancy driving a Toyota Prius? Look no further, Proton is developing electric cars with Detroit Electric Car Company. Made in Malaysia but marketed in Europe? What about being marketed in Malaysia? Anyway, here's the link for more information. How it affects me? Supercapacitor!
More news:
1. CNET UK news: Detroit Electric: Recharge for 21st century
2. Detroit resurrected
3. The Business Insider: Detroit selling electric cars
4. AFP: Proton and Dutch company for Electric Cars
5. Autocar.co.uk: Proton's plug-in cars


Interesting times.

Just for Laugh

I received this in the email today. I like Calvin and Hobbs and used to own quite a few C&H pjs long time ago. Click on the pix for a larger view.

ISEE'Cap09

First International Symposium on Enhanced Electrochemical Capacitors
To be held at the Université de Nantes from the 29th of June to the 2nd of July

Here's a short description of the symposium which can be found at the website:
Electrochemical capacitors, also called supercapacitors, are electricity storage devices subject to increasing research efforts due to their potential technological impact in a wide variety of applications, from portable electronics to stationary power sources or electrical/hybrid vehicles. The enhancement of energy and power densities, cycle life and safety in use remain strongly related to the choice of electrode materials, electrode/electrolyte interactions as well as electrochemical storage mechanisms in various complex systems.
A few meetings offer the opportunity to gather most renowned experts in the related fields together with non-specialist engineers and researchers who would like to know more about these storage devices identified as major electrochemical systems for the near future. ISEE'Cap09 is a unique opportunity for researchers to give and access an overview of the most recent recent results on electrochemical capacitors, covering a wide range of scientific and technological aspects intimately related to each other for the achievement of enhanced storage devices.

Brief Discussion of the Impact of Material and Supercapacitor Research in Malaysia

An email I received from Meisam from USM:

I would like to introduce myself, Meisam Valizadeh Kiamahalleh, as one of postgraduate student in Universiti Sains Malaysia(USM, Penang). Actually my research filed is supercapacitor materials based on CNTs and transition metal oxides nanocomposites. I am going to submit my research proposal but I don’t know how to write the section of Impact toward society and country due to not to be familiar with Malaysia too much.

According to be Malaysian having a lot of experiences in the same field of supercapacitor, would you please guide me how to write this section of my proposal?

I would be very grateful if you can help me in this case. Nice to know you.

Kindest Regards

Meisam Valizadeh Kiamahalleh

Dear Meisam,

It's a nice surprise to be receiving your email. Certainly, I can give an idea or two about the impact of the research on Malaysian society and technological development, however, I must say that having been overseas for the past 8 years, Malaysia has progressed in many different ways (during my absence) in the advancement of her science and technology fields with various research funding being poured extensively by MOSTI and the Higher Education Ministry.

However, with the introduction and further advancement in material studies especially in the field of supercapacitor, a device which bridges the critical energy and power gap between battery/fuel cell and the conventional capacitor, issues which are of global concerns such as the climate change, green house effect and the scarce sources of fossil fuels can be addressed more effectively. Although this may not be the main concern of a developing country like Malaysia, this would certainly help raise awareness of the society towards environmental issues of such and the need to develop workable solutions.

Nonetheless, advancement in material technology would bring the development of supercapacitors into a new era especially with the investigations of nanomaterials which have attracted much attention of late due to their unique properties and in particular, in terms of supercapacitor where the surface utilisation and accessibility of the materials by the electrolytes for redox reactions to take place are the most important features in their storage mechanisms. This would put Malaysia on the right track in the government's objectives to develop world class research centres at our local universities. New understanding of the material especially those which are reported locally would improve the credibility of local research hence enable investigations to be done locally without having to rely on overseas partners. This would also stop the flow of local funds overseas.

Malaysia is a unique country where much of our research have been lagging behind most developed countries in the world even though we may have one of the best research facilities in our universities. This has been identified as one of the crucial challenges, i.e. to bring able knowledge into the country besides being able to produce Malaysian researches who would be able to come up with innovative if not original/novel research. Supercapacitor being one of the most recent fields which has grabbed much attention among the research community, especially in the area of power sources, electrochemical devices, renewable energy, and electrical/power engineering would certainly be an interesting field to be tapped by local universities in Malaysia. This may be an area worth focusing on in terms of being able to transform the local research into an leading one in the world (especially given that Universiti Sains Malaysia has just recently attained it's Apex University title).

Nonetheless, there is also a comprehensive report which has been compiled by the US department of energy on the state-of-the-art supercapacitors as in the Miller and Butler paper which was presented at the 12th International Seminar on supercapacitors. The priority research directions were clearly identified and if were to be used as guidelines would certainly lead to major improvements in this technology. Thus, this technology has very promising future in Malaysia given that the foundation has been carefully laid out by many researchers since the first patent was filed by Becker.

There would be other impacts on the country and society which I would like to discuss further, but I believe what I have written above would give you a good outline and basis on what to work on in your proposal.

Cheers,
KC

p.s. I hope you wouldn't mind me posting this on my webpage.

Apologies to my Readers

It has been a while since I have last updated my blog. I would like to apologise to my readers who have been following my blog for not updating my blog as often since a month plus ago. I have entered my final stage of my PhD which is the writing up period last November and have had my hands full with the analysis of my data, papers etc since. Please bear with me for time being while I focus on my work at hand, and I will be back in action as soon as everything is over. Fingers crossed that everything will turn out fine...Again, thank you for checking out my blog from time to time. I really appreciate it ;) I hope to blog more about supercapacitors and technology, as well as some personal learned knowledge of life from now on. I hope to keep my blog free of political issues affecting Malaysians, I believe there are always better channels to do that and more concrete actions that can be taken rather than writing about them.

Biocompatible CaTiO3 Nanoparticles by Siew Shee Lim

A colleague of mine, Miss Siew Shee Lim who is a lecturer at the University of Nottingham Malaysia Campus is presenting a very exciting and interesting work on hydrothermal synthesis of biocompatible CaTiO3 nanoparticles at the AIChe 2008 (American Institute of Chemical Engineers) Annual Meeting in Philadelphia. Below is the abstract of her research:
Miss Siew Shee Lim is reachable at SiewShee.Lim@nottingham.edu.my

Hydrothermal Synthesis of Biocompatible CaTiO3 Nanoparticles

SiewShee Lim¹, Michael Cloke¹, Kok Chiang Ng², Jun Jin², and George Z. Chen².

(1) School of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Block C, Jalan Broga, 43500 Semenyih Selangor Malaysia, Semenyih, Malaysia,
(2) School of Chemical and Environmental Engineering, The University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom

Synthetic grafts provide the potential for continuous bone healing sources with reasonable production costs compared to autogenous with high harvesting cost and allografts which might cause pathogenic transmission. Particularly, nanostructured CaTiO3, if immobilised on the surfaces of implants, are expected to promote good osteointegration. This research programme aims to demonstrate this expectation by preparation of nanoparticulates of CaTiO3 and test their bioactivity through incubation in simulated human body fluid. In the current work, CaTiO3 nanoparticles were synthesised via a simple hydrothermal process using TiO2 (p25) as the precursor in alkaline media containing calcium salts. The as-prepared powdery materials were washed with distilled water until the pH value became neutral and dried in oven at 50˚C for 24 hours. The dried samples were characterised by X-ray diffraction analysis (XRD), Scanning Electron Microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX). These analyses confirmed the powdery products from the hydrothermal synthesis to be mostly nanoparticulates of CaTiO3 of about 50 nm in average size. A preliminary investigation of the bioresponsiveness of the obtained samples was carried out by immersion in the simulated human body fluid and incubation at 37˚C for 7, 14 and 28 days. The findings, including an expected layer of hydroxyapatite deposit on the surface of the CaTiO3 nanoparticulates, will be reported.

ECS Transactions Publication 2008

Dear Mr. Ng,

We are happy to inform you that your manuscript, "An Asymmetrical Supercapacitor Based on CNTs/SnO2 and CNTs/MnO2 Nanocomposites Working at 1.7 V in Aqueous Electrolyte", has been published in "ECS Transactions", Volume 16.

Authors: Kok Chiang Ng, Shengwen Zhang, and George Z. Chen
Publication: ECS Transactions
Volume: 16
Issue: 1
Issue Title: Electrochemical Capacitors and Hybrid Power Sources 2008
Page Range: 153 - 162
Publisher: The Electrochemical Society
Year Published: 2008

The Electrochemical Society is pleased that issues 1 through 14 of "ECS Transactions" Volume 16 are now online. Having ECST content available electronically is an enormous asset for our members and also an excellent research tool for the scientific community. Now that authors may submit their manuscripts directly, valuable content from our meetings will no longer go unpublished. Even better, this material will never go out of print. In making all manuscripts available individually, we are able to offer an easier way to obtain the material relating to a specific discipline. All of these factors will combine to give "ECS Transactions" a greater reach in disseminating the important research being performed in the fields of electrochemistry, solid-state science, and allied subjects.

Please visit the ECS Digital Library (http://ecsdl.org/ECST/) for further details about full issues and individual manuscripts.

Best regards,
John Lewis, Associate Director of Conference Publications
ECS - The Electrochemical Society
65 South Main Street, Pennington, NJ 08534-2839
Tel:1.609.737.1902, ext. 120 Fax: 1.609.737.2743