Slajd 1 by chenmeixiu

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									         Proton conductors
Low-temperature systems
•water containing systems. e.g. Nafion, heteropolyacids
•oxoacids and their salts, which show proton conductivity
even in the absence of water due to their self-dissociation,
e.g. CsHSO4 (s=10-3 S cm-1 above 412 K)
•blends of organic compounds exhibiting basic sites with
acids, e.g. H3PO4 or H2SO4.
•Xerogels- amorphous materials obtained by drying of the
inorganic gels synthesised using sol-gel route.


High temperature systems
•oxides, hydroxides and apatites
Proton conductivity of some water containing compounds
                                              200 100                0      T / oC
                                     4
                                                          1 M HCl
                                     2         Nafion
                                          (fully hydrated)               H4SiW12O40 x 28 H2O
                                                                           (heteropolyacid)
                                     0


               log (s T)/ S cm-1 K
                                                                       Zirconium phosphonate
                                                SnO2 x n H2O         containing -SO3H x 5.9 H2O
                                     -2       (particle hydrate)

                                     -4

                                     -6                                        H3UO2AsO4 x H2O

                                                  +
                                     -8       H3O --alumina
                                                                                          ice

                                 -10
                                          2               3             4             5           6
                                                                   1000 T-1/ K-1

     The loss of water, which in most cases takes place at
     temperatures close to the boiling point of water, results in a
     decrease in conductivity
Conductivity of high temperature proton conductors

                                   T / oC      400     200       100          0
                                                                         1M NaOH
                              2

                              0                       Y: SrZrO3
                                     Y2O3
        log (s T)/ S cm-1 K
                                                   (single crystal)
                              -2   (undoped)


                              -4                                        Nd: BaCO3
                                        Ni:KTaO3
                              -6                             Y:SrCeO3

                              -8

                          -10                          Fe:LiNbO3


                                       1               2          3                 4
                                                           -1  -1
                                                     1000 T / K
                                             Nafion
     CF2 CF2        CF2 CF

                            OCF2   CF        OCF2CF2 SO3Na
                                         m            n
                                   CF3
m = 0, 1, 2 ;   n   = 1-5


Heteropolyacid with Keggin structure                      Poly (2-acrylamido-2-methyl-
(e.g. H3PO4x12WO3)                                        1-propane sulphonic acid)

                                                                R   CH2 CH           R
                                                                                 n
                                                                           C    O
                                                                          HN
                                                                    H3C    C    CH3

                                                                         H2C

                                                                     O     S    O

                                                                           OH
     O
                                                    Organic-inorganic
                          Organically
Si                                                  material, synthesised in
                          modified
     O    Si       R'     silicate                  sol-gel process
               O
          Si
                                        Inorganic
     R'        O          R'            organic
          Si              Si            polymer
                                        (ORMOCER)
          P        P      P
                   Si
                   R''Y
 P= polymerisable ligand
 R'=(CH2 )3NH2 , C6 H5
 R"=ionic ligand
 Y= ions
  Polymer electrolytes

  •Acidic groups (-COOH, -SO3H) in side or main chain (part of the
  polymer bachbone),
  e.g. poly (acrylic acid), PAMPS

  •Complexes of polymer with salt or acid: polymer with basic sites in a
  chain is a solvent for the dopant

  •Polymer gels- three component systems, combining polymer matrix
  swollen with dopant solution in an an apropriate solvent

Polymers which may be applied in proton conducting systems should fulfil some
requirements, such as:
- chemical and thermodynamic stability
- specific protonic conductivity
- conductivity range depending on the perspective application, i.e. 10-1- 10-3 S cm-1
for fuel cells and 10-5- 10-7 S cm-1 for sensors or electrochromic devices
- properties independent of the humidity level
- thin film configuration.
The use in electrochromic devices requires also high transparency of membranes
Gel electrolytes

Polymers:
Acrylic and methacrylic polymers (PMMA, PAN,PGMA,PAAM),
poly (vinylidene fluoride), poly (vinyl chloride), PEO

Solvents:
Propylene carbonate, ethylene carbonate, N, N-
dimethylformamide, glymes, N-vinylpyrrolidone

Acids:
Phosphoric acid and its acidic esters, sulfuric acid, sulphonic
acids, phosphonic acids, heteropolyacids
Structure of glycidyl methacrylate and products of its reaction with
                          phosphoric acid

                            b CH                                                     O
                                 3
                                                      c   d e
                    CH 2     C       C       O       CH2 CH CH2          +    HO     P      OH
                    a
                                     O                         O                     OH
                    GMA




                                                                                                       b CH3                                   e
                                                                                                                                   c       d
                                                                   H2O
           b CH3                                                                    (2b)        CH 2       C       C       O       CH2 CH CH2 OH
                                   c   d e                                                      a
       CH2 C        C       O      CH2 CH CH2                                                                      O                       O
       a
                    O                    O           O                                                                         HO          P   OH
 (1)                                         P                      H2O
                                                                                                                                    O
                                                     OH                                             b CH3                                           O
                                         O                                                                                     c   d   e
                                                                                    (2a) CH2           C       C       O       CH2 CH CH2 O         P   OH
                                                                                            a
                                     GMA                                                                       O                       OH           O
       b CH
            3                   c   d  e                                        CH3 b'
                                                                                                                           GMA
  CH2 C         C       O       CH2 CH CH2
                                                                     O    C     C     CH2
  a
                O                    O           O                                    a'
                                                                          O                          CH3 b                             e
                                                                                                                                                    O
                                         P                         d'                                                          c    d
 (3)                                 O           O       CH2       CH     CH2            CH 2        C         C       O       CH2 CH CH2 O         P   OH
                                                         e'               c'               a
                                                                   OH                                          O                       O            O
                                                                                                                                e' CH
                                                                                                                                     2
                                                                                                           b' CH3 O             d' CH OH

                                                                                      (4)           CH2 C              C       O       CH2
                                                                                                    a'                                 c'

                                                                   G.Zukowska, V. Robertson, M. Marcinek, K.R. Jeffrey, J. R. Stevens
                                                                   J.Phys.Chem. B 10 (2003) 5797
   Mechanism of proton transport in polymer electrolytes

Grotthus
Fast exchange of protons („hoping”) between neighbouring molecules




 Vehicle
 Transport of a proton as a part of a bigger species (e.g. anion)
                 DMF-H3PO4 based gels
                         Protonation of DMF

         CH3                                  CH3             CH3
                                                           +
HC   N         + H3PO4           HC       N         HC    N         + H2PO4-
                                      +
 O       CH3                      OH          CH3    OH       CH3




 Proton transport according to Grotthus mechanism




(DMF)H+ (DMF)            (DMF)H+ (DMF)                   (DMF)H+ (DMF)


(DMF)      H+(DMF)       (DMF)        H+(DMF)            (DMF)      H+(DMF)



(DMF)      (DMF)H+       (DMF)        (DMF)H+            (DMF)      (DMF)H+
                   PC-H3PO4 based gels


 H3PO4                                H4PO4+        H2PO4-
               Auto-dissociation of H3PO4 in PC
         Vehicle transport at low acid concentration,
          Grotthus at high (30-40%) concentration




5 H3PO4             2 H4PO4+ + H2PO4- + H3O+ + H2P2O72-
 16.815              0.89      0.42      0.461     0.461
 mol/ l at 311 K
Conductivity isotherms for anhydrous
     proton conducting gels
                    -3.2
   log (s/ S cm )




                    -3.6
  -1




                    -4.0




                    -4.4


                           10   20         30       40   50
                                                           - solvent: DMF
                                     % mas. H3PO4          - solvent: PC
Conductivity of liquid and gel electrolyes
     based on PMMA-PC-H3PO4

                                           (c)


                              (b)


   (a) -2
                   -3

                   -4
    log (s/ cm )
    -1




                   -5

                   -6
                                                                       - gels
                   -7
                                                                       - liquid
                   -8                                                 a)50% mas. H3PO4
                   -9                                                 b)26% mas. H3PO4
                        2.5         3.0    3.5    4.0     4.5   5.0   c)19.5% mas. H3PO4
                                          1000 T-1/ K-1
Conductivity of liquid and gel electrolytes
    based on PGMA-DMF-H3PO4
                                                                          - gels
                                                         (e)              - liquid
                                                                         a)50% mas. H3PO4
                                                  (d)                    b)44% mas. H3PO4
                                                                         c)38% mas. H3PO4
                                        (c)                              d)26% mas. H3PO4
                                                                         e)8% mas. H3PO4
                            (b)
                                                                         e*)5% mas. H3PO4
       (a)
                 -2

                 -3
                                                                     GMA (glycidyl
                 -4
                                                                     methacrylate) reacts with
  log(s/Scm-1)




                 -5                                                  phosphoric acid with
                 -6                                                  formation of acidic
                 -7
                                                                     phosphates (stronger acids
                                                                     than H3PO4) which results
                 -8
                                                                     in increase in conductivity
                 -9
                      2.5         3.0     3.5      4.0   4.5   5.0
                                              1000/ T
NMR measurements of the diffusion of deuterons in the DMF/phosphoric acid
                                                  mixtures and in the PGMA/DMF/H3PO4 gels.
                                                  10


            Diffusion Coefficient (x 10 m s )
           2 -1



                                                    1
           -9




                                                  0.1




                                                 0.01      DMF/D3PO4 40%
                                                           DMF/D3PO4 20%
                                                           DMF/D3PO4 7%
                                                           PGMA/DMF/D3PO4 40%
                                                           PGMA/DMF/D3PO4 20%

                                                0.001
                                                     2.5       2.7         2.9      3.1         3.3    3.5
                                                                                           -1
                                                                 1000/Temperature (K )
                                                                             K.R. Jeffrey, G.Z. Zukowska, and J.R. Stevens
                                                                             J. Chem. Phys. 119 (2003) 2422
A comparison of the diffusion coefficients for the deuterons and phosphorus in
  the samples containing 40% phosphoric acid with and without the polymer
                                     matrix

                                             0.1
                                                                  31
                                                                      P DMF/D3PO4 40%
                                                                  2
                                                                      H DMF/D3PO4 40%
                                                                  31
                                                                      P PGMA/DMF/D3PO4 40%
                                                                  2
                                                                      H PGMA/DMF/D3PO4 40%
      Diffusion Coefficient (x 10 m s )




                                                                                               The measurements were made using
                                    2 -1




                                                                                               the static magnetic field gradient
                                 -9




                                                                                               NMR technique. The diffusion
                                                                                               coefficients for the deuterons are
                                                                                               about a factor of three greater than
                                            0.01
                                                                                               that for phosphorus in comparable
                                                                                               samples. The influence of the gel is to
                                                                                               reduce the diffusion coefficient.




                                           0.001

                                               2.6   2.8    3.0         3.2       3.4    3.6
                                                                          -1
                                                       1000/Temperature (K )
                             Influence of the type of proton donor on
                          conductivity in electrolytes based on PMMA-PC-
                                    DMF (a) and PVdF-DMF (b)


                  -3.00                                (a)                       -2.50                             (b)
                                                                                 -3.00
                  -3.50
log (s / S cm )




                                                               log (s/ S cm )
             -1




                                                                            -1
                                                                                 -3.50
                  -4.00                                                          -4.00

                  -4.50                                                          -4.50
                                                                                 -5.00
                  -5.00
                                                                                 -5.50
                  -5.50                                                          -6.00
                            3.0    3.5    4.0    4.5     5.0                             3.0   3.5    4.0    4.5     5.0
                                         -1   -1                                                     -1   -1
                                   1000 T / K                                                  1000 T / K


                                  - PWA, - diphenyl phosphate, - H3PO4
    Electrochromic device




                     -
+
                     -
+
+                    -
+                    -
+                    -
            ions
                         According to Granqvist
Some applications of electrochromic devices
Magic ink
Modern house

								
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