Systematical electrochemical study on the parasitic shuttle-effect in lithium-sulfur-cells at different temperatures and different rates

Busche, Martin R.; Adelhelm, Philipp; Sommer, Heino; Schneider, Holger; Leitner, Klaus; Janek, Jürgen

doi:10.1016/j.jpowsour.2014.02.075

Cited by 216 publications

(180 citation statements)

References 50 publications

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“…However, the discharge hump was not observed in other studies using pouch cells at low temperatures 10,18,19 . It is possible that such behavior is obscured in larger, multilayer Li-S cells, due to the existence of a temperature gradient and associated differences in resistance and state of charge of the cell layers.…”

Section: Resultscontrasting

confidence: 55%

The Effect of Current Inhomogeneity on the Performance and Degradation of Li-S Batteries

Hunt

Zhang

Patel

et al. 2017

J. Electrochem. Soc.

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The effect of thermal gradients on the performance and cycle life of Li-S batteries is studied using bespoke single-layer Li-S cells, with isothermal boundary conditions maintained by Peltier elements. A temperature difference is shown to cause significant current imbalance between parallel connected single-layer cells, causing the hotter cell to provide more charge and discharge capacities during cycling. During charge, significant shuttle is induced in the hotter Li-S cell, causing accelerated degradation of it. A bespoke multi-tab cell in which the inner layers are electrically connected to different tabs versus the outer layers, is used to demonstrate that noticeable current inhomogeneity occurs during the operation of practical multilayer Li-S pouch cells, which is expected to affect their performance and degradation. The observed thermal and current inhomogeneity should have a direct consequence on battery pack and thermal management system design for real world Li-S battery packs. Lithium-sulfur (Li-S) batteries are a promising post lithium-ion battery technology due to their high theoretical energy density of 2600 Wh/kg along with other potential benefits such as low cost, improved safety and good low-temperature performance.1-4 The main challenges in the commercialization of Li-S batteries are to improve their cycle life, rate performance, charging efficiency, and high-temperature performance. 5,6The performance of Li-S batteries depends on a number of temperature-dependent mechanisms. During discharge, lithium and sulfur react electrochemically to form soluble polysulfide species of different chain lengths, such as Li 2 S 6 and Li 2 S 4 , which are then reduced further to produce Li 2 S, which is insoluble and precipitates. When the cell is subsequently charged, the precipitated Li 2 S must re-dissolve before being oxidized back to sulfur and lithium. The solubility of polysulfides as well as the rates of precipitation and dissolution are dependent on temperature:7,8 high temperatures promote dissolution of both sulfur and Li 2 S, whereas low temperatures limit dissolution and encourage precipitation. Model predictions indicate that a decrease in the solubility of polysulfides and their dissolution rates leads to reduced discharge and charge capacities for Li-S batteries. 9 The power capability of Li-S batteries is also critically dependent on temperature. At low temperatures, Li-S cells suffer from larger polarization from reduced ionic conductivity and diffusion rates, resulting in lower rate performance. 10The polysulfide shuttle, a characteristic phenomenon of the Li-S battery, is itself temperature-dependent. The shuttle is strongly correlated to many of the performance challenges that inhibit the mainstream uptake of Li-S batteries, 5 such as the self-discharge, low charge efficiency and irreversible degradation of Li-S batteries at high statesof-charge (SoC). Shuttle occurs when the highly soluble dissolved long chain polysulfides migrate to the lithium anode, where they react to form shorter ch...

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Section: Resultscontrasting

confidence: 55%

The Effect of Current Inhomogeneity on the Performance and Degradation of Li-S Batteries

Hunt

Zhang

Patel

et al. 2017

J. Electrochem. Soc.

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“…A constant current (0.1C) was applied as short pulses, between which the system was allowed to relax to quasiequilibrium (Materials and Methods). Remarkably, a reversible capacity close to the theoretical value of sulfur (1,667 mAh·g −1 ) was achieved during the first cycle under this quasi-equilibrium condition, which cannot be achieved in nonaqueous systems (32,33). Moreover, the gap between the potential at the end of each pulse (polarization potential, as indicated by the black line in Fig.…”

Section: Resultsmentioning

confidence: 62%

Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility

Yang

Suo

Borodin

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

172

182

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Leveraging the most recent success in expanding the electrochemical stability window of aqueous electrolytes, in this work we create a unique Li-ion/sulfur chemistry of both high energy density and safety. We show that in the superconcentrated aqueous electrolyte, lithiation of sulfur experiences phase change from a highorder polysulfide to low-order polysulfides through solid-liquid two-phase reaction pathway, where the liquid polysulfide phase in the sulfide electrode is thermodynamically phase-separated from the superconcentrated aqueous electrolyte. The sulfur with solid-liquid two-phase exhibits a reversible capacity of 1,327 mAh/(g of S), along with fast reaction kinetics and negligible polysulfide dissolution. By coupling a sulfur anode with different Li-ion cathode materials, the aqueous Li-ion/sulfur full cell delivers record-high energy densities up to 200 Wh/(kg of total electrode mass) for >1,000 cycles at ∼100% coulombic efficiency. These performances already approach that of commercial lithium-ion batteries (LIBs) using a nonaqueous electrolyte, along with intrinsic safety not possessed by the latter. The excellent performance of this aqueous battery chemistry significantly promotes the practical possibility of aqueous LIBs in large-format applications.water-in-salt | rechargeable aqueous battery | aqueous sulfur battery | gel polymer electrolyte | phase separation I n the past two decades, rechargeable lithium-ion batteries (LIBs) have revolutionized consumer electronics with their high energy density and excellent cycling stability, and are the state-of-the-art candidates for applications ranging from kilowatt hours for electric vehicles up to megawatt hours for grids (1, 2). The latter applications in large-format present much more stringent requirements for safety, cost, and environmental friendliness, besides energy density and cycle life. The shortcomings of LIB are mostly due to the flammable and toxic nonaqueous electrolytes and moderate energy densities (<400 Wh·kg −1 ) provided by the electrochemical couples currently used (3). Among the various "beyond Li-ion" high-energy chemistries (>500 Wh·kg −1 ) explored currently, the nonaqueous lithium/sulfur (Li/S) battery based on sulfur as a cathode (theoretical capacity of 1,675 mAh·g −1 ) and metallic lithium as an anode seems to be the most practical, as evidenced by the mushrooming literature and significant advances in this system in the past 5 y (4-7). However, commercialization of this system still faces challenges because of severe safety concerns associated with the dendrite growth of metallic Li anode in highly inflammable ether-based electrolytes (8), and the high self-discharge associated with parasitic shuttling of the intermediate polysulfide species. Moreover, the moisture-sensitive nature of the nonaqueous electrolyte would contribute significantly to the cost of the Li/S battery pack due to the stringent moisture-exclusion infrastructure required during the manufacturing, processing, and packaging of the cells. The indispensabl...

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“…7-9, high areal capacities are a prerequisite for obtaining competitive celllevel specifc energies for litiium-sulfur batteries. However, the rate capability for high sulfur loadings (i.e., high areal capacities) generally is very poor, and the recent study by Busche et al 73 shows that the capacity of Li/S-cells decreases substantially at C-rates above 0.2 h -1 , despite their modest sulfur loadings (1.75 mg S /cm 2 , corresponding to ≈2.9 mAh/cm 2 ) compared to the ≥4 mAh/cm 2 which would be required to yield specific energies competitive with LiBs. In comparison, Figure 10 shows the rate capability and the cyclelife of Li/S-cells with ≈4 mAh/cm 2 and 58 %wt sulfur cathodes with a conventionally used electrolyte composed of DOL/DME (dioxolane/dimethoxyethane) with LiTFSI salt.…”

mentioning

confidence: 99%

Review—Electromobility: Batteries or Fuel Cells?

Gröger

Gasteiger

Suchsland³

2015

J. Electrochem. Soc.

456

367

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This study provides an analysis of the technological barriers for all-electric vehicles, either based on batteries (BEVs) or on H 2 -powered proton exchange membrane (PEM) fuel cells (FCEVs). After an initial comparison of the two technologies, we examine the likely limits for lithium ion batteries for BEV applications, and compare the projected cell-and system-level energy densities with those which could be expected from lithium-air and lithium-sulfur batteries. Subsequently, we will review the current development status of H 2 PEM fuel cells, with particular attention to their viability with regards to the required amount of platinum and the resulting cost and availability constraints. It is widely accepted that global warming is caused by CO 2 emissions and that they must be substantially reduced in order to prevent climate change. Since ≈23% of the world-wide CO 2 emissions are due to transportation, ≈75% of which are contributed by the road sector (numbers from 2012 1 ), a reduction of CO 2 emissions from vehicles is imperative to combat global warming. Towards this goal, many countries have passed legislature to lower passenger vehicle emissions over the long term like, e.g., the European Union mandate for 95 g CO2 /km fleet average emissions by 2020.2 The analysis by Eberle et al. 3 in Figure 1 suggests that this rather ambitious goal can only be met by means of extended range electric vehicles or all-electric vehicles in combination with the integration of renewable energy (e.g., wind and solar). Without increased integration of renewable energy sources and basing the calculations on the current European electricity generation mix, the only vehicle concept which could meet the 95 g CO2 /km target are pure battery electric vehicles (BEV100 in Fig. 1). However, for electricity produced entirely by renewable energy sources, the 95 g CO2 /km target could also be met by extended range electric vehicles with 40 miles all-electric range (E-REV40 in Fig. 1), if 50% of driving is powered by the battery (i.e., the average driving range would have to be below 80 miles), or by fuel cell electric vehicles (FECVs), with hydrogen produced by water electrolysis. While these propulsion concepts look promising, their contribution to CO 2 emission savings in the transportation sector would only be meaningful if their market penetration were substantial. In the absence of government regulations, the latter largely hinges on consumer acceptance, which in turn strongly depends on cost. In addition, in the case of BEVs, recent studies clearly showed that BEV driving range (closely followed by cost) are the predominant variables determining consumer acceptance. 4 In the following we will thus focus on the two vehicle types, which would be capable to meet and exceed the CO 2 emission targets of 95 g CO2 /km on the long-term, viz., pure BEVs and hydrogen powered FCEVs. For both vehicle types, but particularly for the latter, meaningful CO 2 emission reductions require the predominant use of renewable energy, which in turn necess...

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Systematical electrochemical study on the parasitic shuttle-effect in lithium-sulfur-cells at different temperatures and different rates

Cited by 216 publications

References 50 publications

The Effect of Current Inhomogeneity on the Performance and Degradation of Li-S Batteries

The Effect of Current Inhomogeneity on the Performance and Degradation of Li-S Batteries

Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility

Review—Electromobility: Batteries or Fuel Cells?

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