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Nanostructured solid polymer electrolytes for Li and Mg ion batteries

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Nanostructured solid polymer electrolytes for Li and Mg ion batteries Powered By Docstoc
					Nanostructured solid polymer
                       p y
electrolytes for Li and Mg ion batteries


          Lyudmila M. Bronstein


Indiana University, Department of Chemistry,
                     g
            Bloomington 47405


        Workshop on Battery Research, IU,
              November 13, 2009
                        Acknowledgements

    Indiana U                       Sandia National Lab
 Prof. John Carini               Dr. Ganesan Nagasubramanian
 Dr. Robert Karlinsey
 Dr. Barry Stein                    No th C oli Sate U
                                    North Carolina S te
 Mr. Zheng Yi
 Dr. John Tomaszewski                  Prof. Saad Khan
                                       Dr. Angela Sanchez
                                              g
   Dalhousie U
Prof. Josef Zwanziger
Dr. Ulli Werner Zwanziger
Dr       Werner-Zwanziger
   • Goldschmidt AG and BASF for gifts of block
       p
     copolymers.
   • Financial support was provided by the PRF and NASA.
                   Lithium battery


                                            PEO-Li
                                            PEO Li salt is
                                            the prototypical
                                            SPE

                                        •Crystallinity (low
                                                    y       )
                                        conductivity at r.t.)
                                        •Low Li transference
                                        number (0.3)

A modern trend is using SPEs (Li ion conductors) instead
 f liquid     l lik l t l t
of li id or gel-like electrolytes
           Composite polymer electrolytes
              p      p y             y

                                        Inorganic component is
                      PEO+Li salt       formed in situ


filler
particle


              y      pp           y
      • Ability to suppress PEO crystallization or stabilize
        low molecular weight amorphous PEG.
      • Enhancement of mechanical properties.
      • Higher conductivity and Li transference numbers.
              Composite SPE based on AlSi OIC
                                                                       II
                          I                GLYMO
                                                                  PEO + Li triflate
                   (CH3O)3Si               O
Si                Si                                O
                                                                    O:Li = 14:1
     O        O
                                 + Al(O-s-Bu)3
         Al
                                                            Conductivity of ~10-5 S/cm;
                                           Hydrolysis,
     O        O                            condensation,
                                           condensation
Si                Si                       polymerization
                                                               t    f          b    f 05
                                                            Li transference number of ~0.5

                  (    SiO)3Si              O                  Inhomogeneity!!!
                                                        O
                                       -
          + alumina species: (AlO4) ; {AlOx(OH)y(H2O)z}



     Si:Al=4:1
                  ,                                , ,
         Bronstein, L. M. et al. Chem. Mater. 2001, 13, 3678.
         Bronstein, L.M. et al. J.Phys. Chem. B, 2004, 108, 5851
         Karlinsey, R.L. et al. J. Phys.Chem. B, 2004, 108, 918
I. Source of inhomogeneity?
     Al species


II. How to avoid it?
Fully silicate OIC (only trace Al(O-s-Bu)3)
            GLYMO                 TMOS
(CH3O)3Si           O
                        O
                                 Si(OCH3)4
  TEM Images of Calcined Si-OIC with
  Trace Al(O s Bu)3
        Al(O-s-Bu)



Smaller OIC particles furnish homogeneity!!!

                   50 nm                              50 nm



  PEG(600)-55% Si-OIC ith
  PEG(600) 55% Si OIC with         PEG(600) 55% Si OIC with
                                   PEG(600)-55% Si-OIC ith
  0.65 mol. % Al(O-s-Bu)3          1.3 mol. % Al(O-s-Bu)3
            7-11
        D = 7 11 nm                         17-39
                                        D = 17 39 nm

   Bronstein, L.M. et al. Solid State Ionics, 2005, 176, 559.
Electrochemical properties of composite
SPE
SPEs
           Sample                RT, S/cm      Li+       OIC
                                              transf. nanoparticle
                                              numb.     size, nm
  PEG(600)-55% AlSi-OIC          1.5810-5      0.5      30-100
   PEG(600)-55% Si-OIC
      ( )                        3.4510-5      0.7         8-25

 PEG(600)-55% Si-OIC with        2.8410-5      0.8         7-11
               (      )
  0.65 mol.% Al(O-s-Bu)3




     Bronstein, L.M. et al. Solid State Ionics, 2005, 176, 559
Composite SPEs based on block copolymers

                            Pluronic   Tg, C      ,c) S/cm
Block copolymer structure
                            notation
PEO13-b-PPO31-b-PEO13       L64         -55 (-67)   2.310-5

      b PPO b PEO
PEO75-b-PPO31-b-PEO75        68
                            F68          43 (-63)
                                        -43 ( 63)   4.610 5
                                                    4 6 10-5

PEO109-b-PPO41-b-PEO109     F88         -40 (-65)   3.010-5

PEO136-b-PPO52-b-PEO136     F108        -41(-66)    2.510-5

PEO14 (600 MW)              -           -57         2.810-5


     Bronstein, L.M. et al. Chem. Mater. 2007, 19, 6258
 Composite SPEs based on block copolymers
                        15000
                                     Pl-L64-SiO2/Al
                                     Pl-F68-SiO2/Al
                                     Pl-F88-SiO2/Al
                                     Pl-F108-SiO2/Al
                        10000
                 tive
          I, relat




                        5000




                            0
                                1     2          3     4
                                          -1
                                    S, nm
Ordering does not lead to enhanced conductivity, while
the extended interfaces are due to intermixing do!
Composite single-ion conductors

                                     9.1310-5 S/cm
                                     9 1310
                                     0.9 (Na+ transf. #)




                                Structurally weak!




 Bronstein, L.M. et al. Chem. Mater. 2006, 18, 708

				
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