Polyphosphazene solid electrolytes

Blonsky, Peter M.; Shriver, Duward F.; Austin, Paul E.; Allcock, Harry R.

doi:10.1021/ja00334a071

Cited by 515 publications

(302 citation statements)

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“…Cross-linking indeed surpresses the crystallisation (and offers the additional benefit of an increased mechanical stability), but simultaneously deteriorates the segmental mobility and with this the ionic conductivity. Another route towards a reduction of the crystallinity involves the use of inorganic polymers such as polyphosphazene [17][18][19][20] and polysiloxane based materials [21][22][23], in which polyether or related Li coordinating residues are attached to an inorganic backbone. The rather high flexibility of the inorganic backbone entails both, low T g values and a reduced tendency towards crystallisation and thus offers the promise of high ionic conductivity.…”

Section: Salt-in-polymer-electrolytesmentioning

confidence: 99%

Local Li Cation Coordination and Dynamics in Novel Solid Electrolytes

Wüllen¹,

Echelmeyer

Voigt

et al. 2010

Zeitschrift Für Physikalische Chemie

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Ionic TransportResearch on solid ionic conductors for use as electrolytes in all solid state batteries still constitutes a rather vivid branch of today's materials science. Despite enormous efforts, neither the development of a solid electrolyte fulfilling the key requirements such as mechanical stability and high ionic conductivity at ambient temperature has been successful nor has an extended understanding of the local Li coordination motifs in the often amorphous systems been obtained. In this contribution, recent progress both in the development of novel solid state electrolytes with high ionic conductivity and mechanical stability and in the characterization of the local Li coordination motifs in these electrolytes from our laboratory is presented. The work was performed as a project within the framework of the Collaborative Research Centre SFB 458 "Ionic Motion in Materials with Disordered Structures -From Elementary Steps to Macroscopic Transport". Results will be given for polymer electrolytes based on polyethylene oxide (PEO), polyphosphazene (PPZ) and polyacrylonitrile (PAN) with various Li salts, nano-composites of these polymer electrolytes and Al 2 O 3 as a ceramic filler, novel inorganic/organic hybrid electrolytes, in which a mixture of an ionic liquid and Li salt is confined within the pore system of a SiO 2 glass, and a crystalline electrolyte, Li 5 La 3 Nb 2 O 12 . Employing a range of advanced solid state NMR methodologies including dipolar based NMR techniques and pulsed field gradient (PFG) NMR and impedance spectroscopy we were able to obtain a detailed knowledge about the local Li cation coordination motifs and the mechanism of Li transport in these electrolytes. Especially the hybrid electrolytes and the salt rich PAN based polymer electrolytes were identified as rather promising materials which combine a high ionic conductivity and mechanical stability.

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Section: Salt-in-polymer-electrolytesmentioning

confidence: 99%

Local Li Cation Coordination and Dynamics in Novel Solid Electrolytes

Wüllen¹,

Echelmeyer

Voigt

et al. 2010

Zeitschrift Für Physikalische Chemie

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“…This material was also the first polyphosphazene showing ionic conduction if a lithium salt is dissolved [16]. In the meantime polyphosphazenes have covered more application areas, for example as constituents in ion conducting self-assembled polymeric films [18,19].…”

Section: Introductionmentioning

confidence: 96%

“…Among the novel polymer materials investigated, polymers with an inorganic backbone, in particular polysiloxanes [12][13][14][15] and polyphosphazenes [16,17], are considered as very promising. The primary advantages of these inorganic polymers are their highly flexible backbone with enhanced segmental mobility together with a high chemical as well as thermal stability.…”

Section: Introductionmentioning

confidence: 99%

Transport Mechanisms of Ions in Graft-Copolymer Based Salt-in-Polymer Electrolytes

Kunze

Schulz

Wiemhöfer

et al. 2010

Zeitschrift Für Physikalische Chemie

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Polymer Electrolyte / Nuclear Magnetic Resonance / Spin Relaxation / Pulsed Field Gradient NMR / ConductivitySalt-in-polymer electrolytes based on graft copolymers with oligoether side chains and added LiCF 3 SO 3 (LiTf) are investigated concerning the transport and dynamics of the ionic species with respect to applications as Li ion conductors. Polymer architectures are based on polysiloxane or polyphosphazene backbones with one or two side chains per monomer, respectively. NMR methods provide information about molecular dynamics on different length scales: The mechanisms governing local dynamics and long range mass transport are studied on the basis of temperature dependent spin-lattice relaxation rates and pulsed field gradient diffusion measurements for 7 Li, 19 F and 1 H, respectively. The correlation times characterizing local ion dynamics reflect the complexation of the cations by the oligoether side chains of the polymer.7 Li and 19 F diffusion coefficients and their activation energies are rather similar, suggesting the formation of ion pairs and clusters with similar activation barriers for cation and/or anion long-range transport. Activation energies of local reorientations are generally significantly smaller than activation energies of long range diffusion. Long range transport is affected by (1) the coupling of conformational side chain reorientations to the cation movement, and (2) the correlated diffusion of cations and anions within ion pairs. Ion pairs and their dissociation play a major role in controlling the resulting conductivity of the material. Guidelines for material optimization in terms of a maximized conductivity can thus be derived by identifying a compromise between high ionic mobility and good Li complexation by the coordinating side chains.

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“…In all cases, the crystallinity was destroyed but conductivity of salf-containing polymer was not improved. However, lightly cross-linked PEI exhibits much improved mechanical roperties and the incorporation of .05 ole Nal/mole of monomer yields a conductivity of 5xl0 " S/ln at 100 C. 6 have received much atwas synthesized following the procedure of tentlon in recent years as host polymers for Saegusa et a1 8 in which methyliodide initiates dissolved salts. We have shown that linear the ring-opening polymerization of 2-methyl polyethylene ierne (-CH 2 aNN-)n can not only oxazoline in dimethyl formanide.…”

Section: "-mentioning

confidence: 99%