V. Focused Fundamental Research - EERE - U.S. Department of ...

Balsara – UCB
V.D.1 Polymer Electrolytes for Advanced Lithium Batteries (UCB)
synthesized as shown in Figure V - 134. Separate values
for the electronic and ionic conductivity of the P3HT-b-
PEO copolymer mixed with LiTFSI, were determined
using a combination of ac and dc impedance
measurements. The P3HT-b-PEO/LiTFSI mixture was
then used to make a lithium battery cathode with LiFePO 4
as the only other component. All-solid lithium batteries
composed of the cathode described above, SEO solid
electrolyte and a lithium foil as the anode showed
capacities within experimental error of the theoretical
capacity of the battery (Figure V - 135). The ability of
P3HT-b-PEO to serve all of the transport and support
functions required in a lithium battery electrode is thus
demonstrated. The fact that P3HT is a semiconductor
enables design of responsive electrodes.
Figure V - 134: Synthesis of P3HT-b-PEO.
Figure V - 135: Average specific capacities for the first 10 cycles of 10 cells.
Conclusions and Future Directions
We have measured salt diffusion coefficients as a
function of block copolymer morphology. We have
successfully synthesized polymer separators with selfassembled
pores, and are in the process of characterizing a
wider array of morphologies to understand the
underpinnings of ion transport in these systems. Our inhouse
assembly and analysis for pouch cells is now fully
opereational with our first full cell data published in ref. 3.
These data demonstrated that our binder conducted both
ions and electrons to the reaction sites within the cathode.
FY 2011 Publications/Presentations
1. "Effect of Lithium Polysulfides on the Morphology of
Block Copolymer Electrolytes", A.A. Teran, N.P.
Balsara, Macromolecules, accepted 2011.
2. "Effect of Molecular Weight on Conductivity of
Polymer Electrolytes", A.A. Teran, M.H. Tang, S.A.
Mullin, N.P. Balsara, Solid State Ionics,
doi:10.1016/j.ssi.2011.09.021, 2011.
3. "Simultaneous Electron and Ion Conduction in a
Block Copolymer: Application in Lithium Battery
Electrodes", A.E. Javier, S.N. Patel, D.T. Hallinan, V.
Srinivasan, N.P. Balsara, Angewandte Chemie
(Communication), vol. 50, pp 9848–9851, 2011.
4. "Salt Diffusion Coefficients in Block Copolymer
Electrolytes", S.A. Mullin, G.M. Stone, A. Panday,
FY 2011 Annual Progress Report 595 Energy Storage R&D