Comparison of lithium-polymer cell performance with unity and nonunity transference numbers

Thomas, Karen E.; Sloop, Steven E; Kerr, John B.; Newman, John

doi:10.1016/s0378-7753(00)00420-1

Cited by 172 publications

(144 citation statements)

References 7 publications

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“…It is important to recognize that batteries with T Li = 1.0 would be particularly useful for high-discharge applications since they would be less susceptible to deleterious effects arising from concentration polarization. [8,35] Riley et al [30] have measured T Li values as high as 0.98 for Li±hectorite in PC.…”

Section: Full Papermentioning

confidence: 99%

Nanocomposite Electrolytes with Fumed Silica and Hectorite Clay Networks: Passive versus Active Fillers

Walls

Riley

Singhal

et al. 2003

Adv Funct Materials

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The use of nanocomposites constitutes a versatile and robust approach in the development of novel electrolytes with tailored electrochemical and mechanical characteristics. In this study, we examine the morphology, rheology, and ion‐transport properties of two types of nanocomposite electrolyte gels, one consisting of branched silica nanoparticles and the other composed of hectorite clay. In the first system with hydrophobic (fumed) silica, oligomers of poly(ethylene oxide) (PEO), and lithium salt, the silica acts as a passive filler and does not participate in ion transport. The electrochemical properties are controlled by the salt–PEO electrolyte, allowing for ionic conductivities greater than 10–3 S cm–1 at ambient temperature. At sufficiently high concentrations, the silica forms an elastic gel possessing a large open network structure that provides for unimpeded ion mobility. In the second system composed of lithium‐exchanged hectorite filler, the nanoscale platelets serve as the anion. This active filler yields ionic conductivities in excess of 10–4 S cm–1 and lithium transference numbers approaching unity. Similar to fumed silica, the hectorite clay also forms an elastic gel network. However, the morphologies of the two systems are distinctively different both in terms of network structure and characteristic length scale. These morphological differences manifest themselves in different rheological responses with regard to gel modulus and yield stress.

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Section: Full Papermentioning

confidence: 99%

Nanocomposite Electrolytes with Fumed Silica and Hectorite Clay Networks: Passive versus Active Fillers

Walls

Riley

Singhal

et al. 2003

Adv Funct Materials

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“…System modeling [4] of lithium polymer [7] and lithium ion polymer batteries [5,6] shows that during the discharge and charge of these batteries, substantial concentration gradients develop within the composite electrodes and adjacent to the lithium electrode.…”

Section: Resultsmentioning

confidence: 99%

“…Since its known that the mobility of polymers is considerably altered in the presence of nanoparticles [1,2] and surfaces [3], it is important to investigate the ion motion in the regions close to the electrodes. Battery system modeling of gel and dry polymer systems [4][5][6][7] shows that much of the performance loss occurs in the composite structures where the ion transport properties can be quite different from the bulk due to the influence of the surfaces. The recent intense interest in the use of ceramic nanoparticle filler material to alter the transport properties of lithium salts in polymer electrolytes [8][9][10][11][12][13][14][15][16][17][18][19] has generated a considerable body of useful data in this respect that can be used to understand the behavior of composite electrodes as well as membranes.…”

Section: Introductionmentioning

confidence: 99%

Interfacial behavior of polymer electrolytes

Kerr¹,

Han²,

Liu³

et al. 2004

Electrochimica Acta

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Abstract.Evidence is presented concerning the effect of surfaces on the segmental motion of PEO-based polymer electrolytes in lithium batteries. For dry systems with no moisture the effect of surfaces of nano-particle fillers is to inhibit the segmental motion and to reduce the lithium ion transport. These effects also occur at the surfaces in composite electrodes that contain considerable quantities of carbon black nano-particles for electronic connection. The problem of reduced polymer mobility is compounded by the generation of salt concentration gradients within the composite electrode. Highly concentrated polymer electrolytes have reduced transport properties due to the increased ionic cross-linking. Combined with the interfacial interactions this leads to the generation of low mobility electrolyte layers within the electrode and to loss of capacity and power capability. It is shown that even with planar lithium metal electrodes the concentration gradients can significantly impact the interfacial impedance. The interfacial impedance of lithium/PEO-LiTFSI cells varies depending upon the time elapsed since current was turned off after polarization. The behavior is consistent with relaxation of the salt concentration gradients and indicates that a portion of the interfacial impedance usually attributed to the SEI layer is due to concentrated salt solutions next to the electrode surfaces that are very resistive. These resistive layers may undergo actual phase changes in a non-uniform manner and the possible role of the reduced mobility polymer layers in dendrite initiation and growth is also explored. It is concluded that PEO and ethylene oxide-based polymers are less than ideal with respect to this interfacial behavior.Introduction.

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“…Obviously, in order to favor salt dissociation, the anion attached to the polymer chain must be selected among the conjugate bases of a superacid, making synthesis more difficult. It was reported that the use of a single-cation conducting polymer electrolyte should lead to an improvement in the performance of lithium polymer batteries [7,8]. Even if the ionic conductivity of these single ion conductor electrolytes is generally much lower by one order of magnitude than polymer salt complexes, salt concentration gradients are circumvented and voltage losses due to concentration polarization are avoided.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical and NMR characterizations of mixed polymer electrolytes based on oligoether sulfate and imide salts

Chauvin

Alloin

Judeinstein

et al. 2006

Electrochimica Acta

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Comparison of lithium-polymer cell performance with unity and nonunity transference numbers

Cited by 172 publications

References 7 publications

Nanocomposite Electrolytes with Fumed Silica and Hectorite Clay Networks: Passive versus Active Fillers

Nanocomposite Electrolytes with Fumed Silica and Hectorite Clay Networks: Passive versus Active Fillers

Interfacial behavior of polymer electrolytes

Electrochemical and NMR characterizations of mixed polymer electrolytes based on oligoether sulfate and imide salts

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