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FLEXIBLE BATTERY:PAPER BATTERY

(RitikaPanwar, Dr. Vinod Kumar)

(University institute of science)

CHANDIGARH UNIVERSITY

ABSTRACT

As gadgets gets thinner and smaller day by day the biggest problem faced by the electronics industry is the size of the battery. At certain points the weight and size of battery creates an obstacle and to overcome this problem researchers gave us an ultimate solution that is paper battery. As technology tends toward flexible and thinner; paper battery is significant. A paper battery is a kind of flexible battery. By combining CNT and paper (cellulose), paper batteries are formed. It works both as a super capacitor and high energy battery.. Being non-toxic, biodegradable and light weight; paper batteries are able to give a new direction to electronics.

Several applications of paper battery are described in this paper. This paper will elaborate how battery utilize cellulose and CNT in its design for its flexibility. An elaboration on the problems faced by most commonly used batteries like Li-ion, NiCd and NiMH, lead acid battery. A comparison between single walled CNT and multi walled CNT also given in this paper.

Keywords: CNT-carbon nanotubes Li-ion- Lithium Ion NiCd- Nickel Cadmium NiMH- Nickel Metal HydrateINTRODUCTION

A paper battery is an electric battery formed largely of cellulose and having thickness less than printer paper(0.25mm). These batteries are non-corrosive and do not require extensive housing. These batteries are differ from traditional batteries because of their composition. Instead of requiring fixed casing; paper battery can be bent or wrapped. Paper battery can easily fit into tight places and help to make the device thinner and light-weight(1).

Like it is most obvious that the size of the battery is one of its greater advantage. 1.5 is offered by one sq.-inch of battery.

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Fig:a typical conventional battery has a dimension of 90*30*4 mm at 75m while paper battery is a 7cm*4mm*0.3mm size atless than 30m.

EXISTING BATTERIESLithium Ion Battery: These battery can be charged and with Li as negative electrode basically used for smartphones, laptops and all sort of home appliances. It is expensive and having safety issues. It also requires temperature sensor and voltage regulator to avoid over charging, over voltage, over heating etc. The electrolyte of battery is highly reactive and dangerous(2).

NiCd and NiMH(Nickel Cadmium and Nickel Metal Hydrate):These batteries are commonly used for backup power. They contain like Cd which is highly toxic metal.Cd exhibit negative temperature coefft and causes problems during charging.NiMH produce hydrogen gas which can burst the cell. These batteries still used in toys due to low cost than Li-ion(2).

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Lead acid batteries: These are the oldest batteries used for automobile, submarine. The problems associated are toxic nature of lead, corrosion of plate etc(2).

At Standford University, a soft battery developed by Blue Spark Inc. and Enfucell Inc. compared with paper battery. The paper battery is rechargeable and flexible battery while Enfucell battery is having short of both. The energy density of the paper battery is 108 mWh/g and the thickness is about 300µm. Enfucell’s battery is thicker than paper battery and the energy density of paper battery is almost twice than Enfucell’s battery(6).

Fig: energy density comparison (arrow shows the direction of improvement).

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HISTORYAt Rensselaer Polytechnic Institute in Troy, New York, a research team led by Dr. RobertLinhardt with the Ann and John H. Broadbent developed paper battery.Pushparaj, Shaijumon M. Manikoth, Anshwani Kumar and SaravanababuMurugeson were co-authors and lead the project of researchers. Other co-authors were Lijie Ci and Robert Vajtai(Rensselaer Nanotechnology Laboratory Manager (2,3,4).

CARBON NANOTUBE AND ITS TYPEIn 1991, a Japanese scientist discovered CNT. CNTs are made from graphite. CNTs are allotropes of carbon. CNTs are third allotropic form of carbon(2).If inhaled, interact with the microphages present in human body (similar to Asbestos fiber) and may cause to tumor progression and metastasis in lungsAsbestos: Aesbestos is a naturally occurring mineral composed of a soft and flexible fiber. It can be used to make plastic, cement, paper, cloth and other material to make them stronger. The mineral fiber can permanently trapped in the body if inhaled or ingested and may cause to cancer or lungs disease (13,14).

(a)microscopic image of asbostos fiber (b)microscopic image of CNTs Fig: Similarity between Assbostos fiber and CNTs CNTs are of two type:1.Single walled CNTs (SWCNT): SWCNT are made from single layer of graphene and can be twisted easily(2).

2.Multi walled CNTs (MWCNT): MWCNT are made from multiple layer of graphene and difficult to twist(2).

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(a) SWCNT(b)MWCNT(c)TEM image of SWCNT(d)TEM image of MWCNT

The Main Ingredient Paper

Since paper is combustible and biodegradable so disposing of paper is also cheap. The flexibility of paper battery is also because of paper. The use of paper in paper batteries increase the flow of electrons. Paper allows the flow of electrolytes in battery(1).According to researchers of Stanford University, the self discharge of battery is less. The experiment demonstrates that paper is stable in electrolyte.The paper having CNT thickness from 100nm to 5µm can be bent down to a 2mm radius or there will not be any measurable change in its electrical conductivity if it is folded. According to fatigue test, there will only less than 5% increase in the resistance if the paper is bent down to 2mm for 100 times. The requirement in superconductors and battery could be satisfied by such kind of flexibility (16).

Fig:resistance changing with radii MECHANICSPaper battery consist of two electrodes, a separator, an electrolyte (including bio electrolyte like sweat, blood and urine) and charge collector. One electrode of paper battery made up of conductive CNT and the another one is prepared from the coating of lithium oxide on opposite side of separator. This separator (paper) is made up of plant cellulose. It is saturated with organic salt to provide electrolyte (6). The battery does not require any sealed case (5).

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As electrode is CNTs and anode is metal, a chemical reaction occurs and electrons flow. The flow of electrons will be from negative to positive terminal for the reaction (1,3). If the battery is dipped in ion-based liquid then the working of the battery starts i.e. by the movement of the electrons from cathode to anode, electricity is generated. A chemical reaction occurs between the liquid and the electrodes of the battery. During the recharging of battery, the energy is stored in paper electrode due to quick flow of ions within a few second (10sec). The output of paper battery can be increased, by stacking various paper battery up on each other. FABRICATIONComponents: It consist of following components:1. CNTs are used as cathode.2. Lithium metal ( Li+) as anode.3. Paper (cellulose) is used as separator.4. All electrolytes (including bio electrolyte like sweat, blood).Separator: It prevents the cathode and anode from touching or can be said that it works as permeable membrane between the two. It allows the electrons to flow.Black Carbon Ink: BCI is a solution of ionic salt solution, surface adhesive agent and nano-rods.

(a)flexible paper battery (b)SEM imageThe Scanning Electron Microscope( SEM) image shows the three components of paper battery from which the battery is made of.Steps to do:1. Firstly, black carbon ink is applied on a cellulose based paper. 2. Black carbon ink is being spread on paper.3. A thin film of Li is laminated over the cellulose surface.4. At 80°C, the cellulose paper is heated for 5 minutes.5. The film is peeled off from the substrate.6. This film acts as electrode of paper battery.7. One electrode (film) is connected to lithium titanium oxide (Li4Ti5O12) and another film pasted to lithium cobalt oxide (LiCoO2).

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8. At last, connect a LED to check the functionality.

Variation On Structure

Yet another change to the structure has been proposed by the assistant professor, Yi Cui of Standford University, he found that using a chemical vapor deposition technique, at the anode in the place of CNTs silicon nanowires can be synthesized and used.

As per another battery design CNTs can be used in the form of charge collecto. Random network of nanotubes can replace the metal in the charge collector, and nanotubes take the place of carbon black.

Fig: Proposed single layer battery structure

A mixture of nanotubes and active material is contained by this layer(6).

APPLICATIONCosmetic:Paper battery are embedded into cosmetic patches for many applications like wrinkles, skin whitening and antiaging(6,7).

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TrackingDevice: Tracking devices like RFID are made using paper battery. RFID stands for Radio Frequency Identification Device. These tags used to track the assets. Companies can place smart labels, RFID tags on almost all products by using paper battery(6,8).Medical Care:This battery can be used to make devices like pacemaker. This is an electrical device used to constantly monitor the heart beats. Patients can hold it easily inside their body(6,9).FUTURE ASPECTSMost of the electronic appliances have battery. With the use of more flexible batteries electronics can take any shape. Paper battery has been the potential to revolutionize the world in aspects of power. CONCLUSIONPaper battery is playing a good role in the field of electronics; in making devices flexible, thinner. With endless possibilities of paper battery our daily lives are going to change in future. It will save cost and in a sense lives also. The combination of CNTs and conventional sheet of paper results to a flexible and thin device which is used to store energy. As compared to conventional batteries they have light weight and consume less space. Paper battery is environment friendly as well as human friendly as it is both non-toxic and biodegradable. As now-a-days recycling is a major problem it fulfills that stance also. Paper batteries have have the monopoly in powering the electronic devices as it is the technology of future.REFERENCE1.Anil Tekale, Swapna God, Dinesh Nawani, akshay Pachpute, Sagar Bhapkar, International Journal of Advanced Research in Electrical Electronics and Instrumentation Engineering(IJAREEIE),Vol-6,Issue9, September 20172.Syed Sibghatullah Quadri, Syed Sameer, Pathan Jawwad Khan, Shaikh Shoeb, IJARIIE-ISSN(O)-2395-4396, vol-3,Issue-3,20173.Tejaswi Kadam, Prasad C. Shinde, and prof. U. C. Patkar, Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-5,2016 ISSN:2454-1362, http://www.onlinejournal.in4.A. Ganguly, S. Sar, International Journal of Advanced Engineering Research and Studies (IJAERS)IJAERS/VOL-1/ISSUE-1/October-December,2011/130-1335.International journal of Engineering Research and Technology (IJERT) Vol-5,Issue23 ISSN:2278-0181 www.ijert.org6.S. Balu, M. Mahalakshmi, International Journal of Science and Research (IJSR), ISSN(online):2319-7064, Impact Factor(2012):3.358.www.ijsr.net7.http://www.powerpaper.cn/indexbda1.html?categoryId=438798.https://www.camcode.com/asset-tags/what-are-rfid-tags/9.https://www.bhf.org.uk/informationsupport/treatments/pacemakers10.https://www.researchgate.net/figure/Fig-3-Paper-Battery-applications-REFRENCES_fig5_281646438

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11. L. Hu., H. Wu, F. Mantia, Y. Yang, Y. Cui. (2010, September). “Thin, Flexible Secondary Li-Ion Paper Batteries.” American Chemical Society. [Online Article]. Available:http://pubs.acs.org/doi/pdfplus/10.1021/nn1018158

12. A. Kiebele and G. Gruner. (2007, October). “Carbon Nanotube Based Battery Architecture.” Applied Physics Letters. [Online Article]. Available:http://apl.aip.org/resource/1/applab/v91/i14/p144104_s1?view=fulltext

13.https://www.researchgate.net/figure/Microscopic-view-of-fibres-a-asbestos-b-CNTs_fig6_297251628

14.https://www.asbestos.com/asbestos/

15.https://www.researchgate.net/figure/fig1_255773731

16.Liangbing hu, Jang Wook Choi, Yuan yang, Sangmoo Jeong, Fabio La Mantia, Li Feng Cui, Yi Cui, www.pnas.org/cgi/doi/10.1073/pnas.0908858106

17.J.Mater.Chem.A,2013,1,4671-4677,journal is ©the royal society of chemistry 2013, https://www.researchgate.net/publication/255773731