The authors would like to thank Weatherford International for providing financial support.

1. Graft Copolymer Synthesis18-19
<ol>
 <li>Synthesize the graft copolymers (POEM-g-PDMS and POEA-g-PDMS at 70:30 weight ratio) using a free radical polymerization approach by mixing 26 ml of POEM (or POEA) monomers (Figure 3), 12 ml of PDMS macromonomers, and 12 mg of 2,2'-Azobis(2-methylpropionitrile) (AIBN) (monomer:initiator [825:1]) in 160 ml of EA.</li>
 <li>Seal the flask containing the clear solution with a rubber septum and purge with ultra high purity argon for 45 min.</li>
 <li>He...

<ol>
	<li>Tarascon, J. M., Armand, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Issues+and+challenges+facing+rechargeable+lithium+batteries.">Issues and challenges facing rechargeable lithium batteries.</a> Nature. 414 (6861), 359-367 (2001).</li><li>Scrosati, B., Hassoun, J., Sun, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lithium-ion+batteries.+A+look+into+the+future.">Lithium-ion batteries. A look into the future.</a> Energy Environ. Sci. 4 (9), 3287-3295 (2011).</li><li>Goodenough, J. B., Kim, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+for+rechargeable+batteries.">Challenges for rechargeable batteries.</a> J. Power Sources. 196 (16), 6688-6694 (2011).</li><li>Wang, Y., He, P., Zhou, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Olivine+LiFePO4:+development+and+future.">Olivine LiFePO4: development and future.</a> Energy Environ. Sci. 4 (3), 805-817 (2011).</li><li>Bruce, P. G., Scrosati, B., Tarason, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanomaterials+for+rechargeable+lithium+batteries.">Nanomaterials for rechargeable lithium batteries.</a> Angew. Chem. 47 (16), 2930-2946 (2008).</li><li>Choi, N., Yao, Y., Cui, Y., Cho, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One+dimensional+Si/Sn+-+based+nanowires+and+nanotubes+for+lithium-ion+energy+storage+materials.">One dimensional Si/Sn - based nanowires and nanotubes for lithium-ion energy storage materials.</a> J. Mater. Chem. 21 (27), 9825-9840 (2011).</li><li>Jeong, G., Kim, Y. U., Kim, H., Kim, Y. J., Sohn, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prospective+materials+and+applications+for+Li+secondary+batteries.">Prospective materials and applications for Li secondary batteries.</a> Energy Environ. Sci. 4 (6), 1986-2002 (2011).</li><li>Walker, C. W., Salomon, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvement+of+ionic+conductivity+in+plasticized+PEO-Based+solid+polymer+electrolytes.">Improvement of ionic conductivity in plasticized PEO-Based solid polymer electrolytes.</a> J. Electrochem. Soc. 140 (12), 3409-3412 (1993).</li><li>Daniels, C., Besenhard, J. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of battery materials. , (2011).</li><li>Bard, A. J., Faulkner, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Electrochemical methods: fundamentals and applications. , 864 (2001).</li><li>Newman, J., Thomas-Alyea, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Electrochemical systems. , 672 (2004).</li><li>Zu, C., Li, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermodynamic+analysis+on+energy+densities+of+batteries.">Thermodynamic analysis on energy densities of batteries.</a> Energy Environ. Sci. 4 (8), 2614-2624 (2011).</li><li>Balbuena, P., Wang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Lithium-ion Batteries: solid-electrolyte interphase. , (2004).</li><li>Appetecchi, G. B., Scaccia, S., Passerini, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+on+the+Stability+of+the+Lithium-Polymer+Electrolyte+Interface.">Investigation on the Stability of the Lithium-Polymer Electrolyte Interface.</a> J. Electrochem. Soc. 147 (12), 4448-4452 (2000).</li><li>Bruce, P. G., Krok, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterisation+of+the+electrode/electrolyte+interfaces+in+cells+of+the+type+Li/PEO+LiCF3SO3/V6O13+by+ac+impedance+methods.">Characterisation of the electrode/electrolyte interfaces in cells of the type Li/PEO LiCF3SO3/V6O13 by ac impedance methods.</a> Solid State Ionics. 36 (3-4), 171-174 (1989).</li><li>Huggins, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Energy Storage. , 400 (2010).</li><li>Lee, S., Sch&#246;mer, M., Peng, H., Page, K. A., Wilms, D., Frey, H., Soles, C. L., Yoon, D. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlations+between+ion+conductivity+and+polymer+dynamics+in+hyperbranched+poly(ethylene+oxide)+llectrolytes+for+lithium-ion+batteries.">Correlations between ion conductivity and polymer dynamics in hyperbranched poly(ethylene oxide) llectrolytes for lithium-ion batteries.</a> Chem. Mater. 23 (11), 2685-2688 (2011).</li><li>Trapa, P. E., Reyes, A. B., Das Gupta, R. S., Mayes, A. M., Sadoway, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polarization+in+cells+containing+single-ion+graft+copolymer+electrolytes.">Polarization in cells containing single-ion graft copolymer electrolytes.</a> J. Electrochem. Soc. 153 (6), 1098-1101 (2006).</li><li>Trapa, P. E., Won, Y. Y., Mui, S. C., Olivetti, E. A., Huang, B., Sadoway, D. R., Mayes, A. M., Dallek, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rubbery+graft+copolymer+electrolytes+for+solid-state+thin-film+lithium+batteries.">Rubbery graft copolymer electrolytes for solid-state thin-film lithium batteries.</a> J. Electrochem. Soc. 152 (1), A1-A5 (2005).</li><li>Walker, C. W., Salomon, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvement+of+ionic+conductivity+in+plasticized+peo-based+solid+polymer+electrolytes.">Improvement of ionic conductivity in plasticized peo-based solid polymer electrolytes.</a> J. Electrochem. Soc. 140 (12), 3409-3412 (1993).</li><li>Bard, A. J., Faulkner, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Electrochemical methods: fundamentals and applications. , 864 (2001).</li><li>Michnick, R. B., Rhoads, K. G., Sadoway, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relative+dielectric+constant+measurements+in+the+butyronitrile-chloroethane+system+at+subambient+temperatures.">Relative dielectric constant measurements in the butyronitrile-chloroethane system at subambient temperatures.</a> J. Electrochem. Soc. 144 (7), 2392-2398 (1997).</li><li>Orazem, M. E., Tribollet, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Electrochemical impedance spectroscopy. , (2008).</li><li>Cogger, N. D., Evans, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+introduction+to+electrochemical+impedance+measurement.">An introduction to electrochemical impedance measurement.</a> Technical Note, Solartron Analytical Technical Report. No. 6, (1999).</li><li>Marzantowiz, M., Dygas, J. R., Krok, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impedance+of+interface+between+PEO:LiTFSI+polymer+electrolyte+and+blocking+electrodes.">Impedance of interface between PEO:LiTFSI polymer electrolyte and blocking electrodes.</a> Electrochim. Acta. 53 (25), 7417-7425 (2008).</li><li>Clarson, S. J., Semlyen, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+of+cyclic+and+linear+poly(dimethyl-siloxanes):+21.+high+temperature+thermal+behavior.">Studies of cyclic and linear poly(dimethyl-siloxanes): 21. high temperature thermal behavior.</a> Polymer. 27 (1), 91-95 (1986).</li></ol>

The LiFePO4/GCE/Li curves show greater overpotential than the LiFePO4/LP30/Li curves on both charge and discharge. Since the GCE is used as both electrolyte and binder, ion conduction is provided to all of the cathode particles, and nearly the entire practical specific capacity (150 mAh/g) was accessible. The theoretical specific capacity of 170 mAh/g is not achieved since it is limited by lithium diffusion within LiFePO4 particles, which is low at room temperatures. The cycling capacitie...

Lithium (Li) is a highly electropositive metal (-3.04 V relative to standard hydrogen electrode), and the lightest metal (equivalent weight of 6.94 g/mol and specific gravity of 0.53 g/cm3). This makes it attractive as a choice for the active material in the negative electrode and ideal for portable energy storage devices where size and weight matter. Figure 1 shows that lithium-based batteries (Li ion, PLiON, and Li metal) have higher energy densities than lead-acid, nickel-cadmium, and nickel-metal-hydride batteries 1.
A full lithium-ion battery consists of a cathode (positive), an anode (negative), an electrolyte, and a separator (Figure 2). Both the cathode and the anode are intercalation compounds, where Li-ions can intercalate or de-intercalate reversibly (if the anode is carbon, Li intercalates as neutral Li). The electrolyte provides ionic conduction and insulates electronic conduction between the electrodes. The separator is permeable to ions, but mechanically rigid to keep the two electrodes from shorting. When the cell is in a fully charged state all of the Li has intercalated in the anode, and when the cell is in a fully discharged state all of the Li-ions are intercalated in the cathode. During the spontaneous reaction, discharging electrons flow from the anode to the cathode through an external circuit to power a device, while the ions flow from the anode to the cathode through the electrolyte. The ions and electrons recombine at the cathode to maintain charge neutrality. Upon charging, the flow is reversed.
Most Li-ion battery development to date has focused on cathode materials because they determine the energy density of the battery rather than on the electrolyte, which has remained mostly the same for decades. The electrolyte is a key piece of the battery since it affects the overall power capability due to impedance both through the electrolyte itself and at the electrode-electrolyte interfaces.
The electrolyte used in Li-ion batteries generally consists of a salt of the type LiX and a non-aqueous solvent. Compared to the aqueous electrolytes used in other electrochemical systems, the disadvantages of Li-ion electrolytes are lower conductivity, higher cost, flammability, and environmental problems. Advantages include a wide temperature range (over which the electrolyte remains a liquid) from -150 &deg;C to 300 &deg;C, a wide voltage window (up to 5 V versus Li/Li+), and better compatibility with electrodes (aqueous electrolyte would react violently with Li metal and form LiOH and hydrogen) 2, 3, 4-6.
The main non-aqueous electrolytes used in batteries include organic carbonate-based liquids, polymers, ionic liquids, and ceramics. These electrolytes need to meet certain benchmarks to be used in practical Li-ion batteries. They include a conductivity of at least 10 mS/cm, a large electrochemical window (&gt;4.5 V for high voltage cathodes), low vapor pressure, good thermal and chemical stability, low toxicity, and low cost. For certain stringent applications such as the electric vehicles, all of these benchmarks must be met over a wide temperature range, typically from -20 &deg;C to 60 &deg;C. Since the focus of this work is on organic and polymer electrolytes, the remainder of this paper will focus on these electrolytes.
Carbonate based electrolytes consist of a lithium salt dissolved in an organic solvent. However, it is difficult for any one solvent to meet all of the requirements. For example, solvents with low vapor pressure, such as ethylene carbonate (EC) and propylene carbonate (PC), tend to have higher viscosities, leading to lower conductivity. Also EC is a solid at room temperature; this requires it to be combined with another solvent. Generally the electrolyte is a combination of several solvents. The common solvents and some of their physical properties are listed in Table 1.
<table border="1">
 <tbody>
 <tr>
 <td>Name</td>
 <td>Melting Temperature (&deg;C)</td>
 <td>Boiling Temperature (&deg;C)</td>
 <td>Viscosity (mPa*s)</td>
 </tr>
 <tr>
 <td>Dimethyl Carbonate (DMC)</td>
 <td>4.6</td>
 <td>90</td>
 <td>0.5902 (25 &deg;C)</td>
 </tr>
 <tr>
 <td>Diethyl Carbonate (DEC)</td>
 <td>-43</td>
 <td>126.8</td>
 <td>0.7529 (25 &deg;C)</td>
 </tr>
 <tr>
 <td>Ethylene carbonate (EC)</td>
 <td>36.5</td>
 <td>238</td>
 <td>1.9 (40 &deg;C)</td>
 </tr>
 <tr>
 <td>Propylene Carbonate (PC)</td>
 <td>-54.53</td>
 <td>242</td>
 <td>2.512 (25 &deg;C)</td>
 </tr>
 </tbody>
</table>
Table 1. Common Carbonate Solvents 7.
Safer alternates to organic electrolytes are polymer based electrolytes. Polymer electrolytes are thin-films, non-volatile, non-flammable, and their flexibility allows them to be rolled and printed on a large commercial scale. Wright, et al. first demonstrated ion conduction in poly(ethylene oxide)-salt complexes (PEO) in 1973. It was later discovered that the safety concern associated with dendrite growth on Li metal in liquid electrolyte could be resolved by using PEO-based solid polymer electrolyte, which suppressed the growth of dendrites 8-17. There are three main types of polymer electrolytes: (1) solvent free dry solid polymer, (2) gel electrolytes, and (3) plasticized polymer, with a solvent free dry synthesis used in our work.
This paper will discuss (a) the solvent free dry polymer synthesis, (b) the polymer conduction mechanism, and (c) provide temperature cycling for both solid polymer and organic electrolytes.

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments (optional)</td>
		</tr>
		<tr>
			<td>POEM</td>
			<td>Sigma Aldrich</td>
			<td>26915-72-0</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>POEA</td>
			<td>Sigma Aldrich</td>
			<td>32171-39-4</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>LiTFSI</td>
			<td>Sigma Aldrich</td>
			<td>90076-65-6</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>AIBN</td>
			<td>Sigma Aldrich</td>
			<td>78-67-1</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>EA</td>
			<td>Sigma Aldrich</td>
			<td>141-78-6</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>THF</td>
			<td>Sigma Aldrich</td>
			<td>109-99-9</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>PDMS</td>
			<td>Gelest</td>
			<td>146632-07-7</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Argon Gas</td>
			<td>Air Gas</td>
			<td>&nbsp;</td>
			<td>Ultra high purity (Grade 5)</td>
		</tr>
		<tr>
			<td>PE</td>
			<td>Sigma Aldrich</td>
			<td>8032-32-4</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>LiFePO4</td>
			<td>Gelon</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Carbon black</td>
			<td>SuperP</td>
			<td>&nbsp;</td>
			<td>Super P</td>
		</tr>
		<tr>
			<td>Lithium metal</td>
			<td>Alfa Aesar</td>
			<td>7439-93-2</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>PVDF binder resin</td>
			<td>Kynar</td>
			<td>&nbsp;</td>
			<td>Kynar</td>
		</tr>
		<tr>
			<td>PVDF Separator</td>
			<td>Celgard</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>LP30</td>
			<td>Merck</td>
			<td>&nbsp;</td>
			<td>LiPF6 in EC:DMC</td>
		</tr>
		<tr>
			<td>MACCOR battery tester</td>
			<td>MACCOR</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>El-Cut</td>
			<td>EL-CELL</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

solid-state graft copolymer electrolytes for lithium battery applications

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (&lt;80 &deg;C), flammable, and volatile organic electrolytes. These organic based electrolyte systems are viable at ambient temperatures, but require a cooling system to ensure that temperatures do not exceed 80 &deg;C. These cooling systems tend to increase battery costs and can malfunction which can lead to battery malfunction and explosions, thus endangering human life. Increases in petroleum prices lead to a huge demand for safe, electric hybrid vehicles that are more economically viable to operate as oil prices continue to rise. Existing organic based electrolytes used in lithium ion batteries are not applicable to high temperature automotive applications. A safer alternative to organic electrolytes is solid polymer electrolytes. This work will highlight the synthesis for a graft copolymer electrolyte (GCE) poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature (Tg) poly(oxyethylene) acrylate (POEA). The conduction mechanism has been discussed and it has been demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence. Batteries containing commercially available LP30 organic (LiPF6 in ethylene carbonate (EC):dimethyl carbonate (DMC) at a 1:1 ratio) and GCE were cycled at ambient temperature. It was found that at ambient temperature, the batteries containing GCE showed a greater overpotential when compared to LP30 electrolyte. However at temperatures greater than 60 &deg;C, the GCE cell exhibited much lower overpotential due to fast polymer electrolyte conductivity and nearly the full theoretical specific capacity of 170 mAh/g was accessed.

The room temperature cell cycling performance is shown in Figure 8. The left plot shows the charge and discharge profiles of cells with conventional liquid electrolyte (LP30) at 15 mA/g, and GCE/binder at 10 mA/g. Figure 9 shows the discharge voltage profiles of the solid polymer cells at room temperature, 60 &#176;C, and 120 &#176;C using a low current of 0.05 C. The discharge voltage profiles as functions of specific capacity are shown in Figure 10,where the discharge ...

Watch this Scientific Journal Video about Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications at JoVE.com

Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications

Lithium ion batteries employ flammable and volatile organic electrolytes that are suitable for ambient temperature applications. A safer alternative to organic electrolytes are solid polymer batteries. Solid polymer batteries operate safely at high temperatures (&gt;120 &deg;C), thus making them applicable to high temperature applications such as deep oil drilling and hybrid electric vehicles. This paper will discuss (a) the polymer synthesis, (b) the polymer conduction mechanism, and (c) provide temperature cycling for both solid polymer and organic electrolytes.

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (&lt;80 ...

solid-state-graft-copolymer-electrolytes-for-lithium-battery

Research

JoVE Journal

Engineering

21.4K visualizações.  Massachusetts Institute of Technology. As baterias de iões de lítio empregam eletrólitos orgânicos inflamáveis ​​e voláteis que são adequados para aplicações de temperatura ambiente. Uma alternativa mais segura para os eletrólitos orgânicos são baterias de polímero sólido. Baterias de polímero sólido operar com segurança em altas temperaturas (> 120 ° C), tornando-os aplicáveis ​​para aplicações de alta temperatura, como perfuração de petróleo profundo e veículos elétricos ...