Electrochemistry and the Future of the Automobile

Wagner, Frederick T.; Lakshmanan, Balasubramanian; Mathias, Mark F.

doi:10.1021/jz100553m

Cited by 742 publications

(647 citation statements)

References 51 publications

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“…This volume expansion at a given pressure can be calculated by 5: V = RT n CO 2 (total) p − V el c el K H [5] To assess how much pressure buildup or volume expansion would actually occur in a commercial-scale cell containing 2.5 wt% lithium oxalate in the cathode electrode, we use a similar approximation for a commercial-scale 3 Ah cell as shown in ref. 16, where the weight for cathode active material and electrolyte solution were taken from Wagner et al 57 Furthermore, we also calculate the expected volume expansion for a 180 mAh pouch cell containing ∼ 0.75 mL electrolyte solution as used by Xia et al, 58 assuming a constant pressure of 1 bar in the cell. In both cases, the composite cathode is approximated to consist of 96% active material and 2.5 wt% lithium oxalate.…”

Section: Discussionmentioning

confidence: 99%

Lithium Oxalate as Capacity and Cycle-Life Enhancer in LNMO/Graphite and LNMO/SiG Full Cells

Solchenbach

Wetjen

Pritzl

et al. 2018

J. Electrochem. Soc.

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In the present study, we explore the use of lithium oxalate as a "sacrificial salt" in combination with lithium nickel manganese spinel (LNMO) cathodes. By online electrochemical mass spectrometry (OEMS), we demonstrate that the oxidation of lithium oxalate to CO 2 (corresponding to 525 mAh/g) occurs quantitatively around 4.7 V vs. Li/Li + . LNMO/graphite cells containing 2.5 or 5 wt% lithium oxalate show an up to ∼11% higher initial discharge capacity and less capacity fade over 300 cycles (12% and 8% vs. 19%) compared to cells without lithium oxalate. In LNMO/SiG full-cells with an FEC-containing electrolyte solution, lithium oxalate leads to a better capacity retention (45% vs 20% after 250 cycles) and a higher coulombic efficiency throughout cycling (∼1%) compared to cells without lithium oxalate. When CO 2 from lithium oxalate oxidation is removed after formation, a similar capacity fading as in LNMO/SiG cells without lithium oxalate is observed. Hence, we attribute the improved cycling performance to the presence of CO 2 in the cells. Further analysis (e.g., FEC consumption by 19 F-NMR) indicate that CO 2 is an effective SEI-forming additive for SiG anodes, and that a combination of FEC and CO 2 has a synergistic effect on the lifetime of full-cells with SiG anodes. Lithium nickel manganese spinel (LiNi 0.5 Mn 1.5 O 4 , LNMO) is a promising cathode material for high energy lithium ion batteries due to its high operating potential around 4.7 V vs. Li/Li + , its high rate capability, structural stability and the absence of cobalt. However, its lower specific capacity (146 mAh/g LNMO ) compared to layered oxide materials (e.g. lithium nickel manganese cobalt oxide (NMC), specific capacity 150-250 mAh/g NMC ) 1 is regarded as a major drawback. In full-cells, the practically achievable capacity of LNMO is even lower, as the formation of the solid-electrolyte interphase (SEI) on the graphite anode consumes active lithium. For many layered oxide cathodes, however, the first cycle irreversible capacity of the cathode is similar to the capacity needed for SEI formation (∼20 mAh/g NMC ), and hence the practical discharge capacity of the cathode and the remaining active lithium are more or less balanced again. 2,3 In contrast, the first cycle irreversible capacity of LNMO (∼6 mAh/g LNMO ) is much lower than the capacity needed for SEI formation. This leads to a mismatch between active lithium and practical cathode capacity, i.e., there is not enough active lithium available to fully discharge the LNMO cathode during subsequent cycling.In cells with silicon-based anodes, active lithium losses on the anode are even higher compared to graphite, as the expansion of the silicon particles during the first lithiation leads to a continuous exposure of fresh, unpassivated silicon surface. 4 On this new surface, electrolyte reduction occurs instantaneously, which reduces the total lithium reservoir in the cell. Therefore, different ideas to increase the amount of active lithium in lithium ion full-cells have been suggested, ...

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Section: Discussionmentioning

confidence: 99%

Lithium Oxalate as Capacity and Cycle-Life Enhancer in LNMO/Graphite and LNMO/SiG Full Cells

Solchenbach

Wetjen

Pritzl

et al. 2018

J. Electrochem. Soc.

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“…However, their estimation did not take into account the effect of increased Pt consumption from PEMFC production on the supply of Pt.x Making provisions for supply constraints, the same authors have revised this quantity and suggest that a 4-10-fold improvement in ORR activity over pure Pt would be necessary. 1,6,23 In this perspective article, we review the current understanding of the ORR on Pt and its alloys, providing selected examples from the literature. We focus specifically on the factors governing the stability and activity of these materials, and make several suggestions for future directions in the field.…”

Section: Ulrik Grønbjergmentioning

confidence: 99%

“…† The anode loading could be dropped to 0.05 mg cm À2 without measurable kinetic losses. 5 However, 0.4 mg cm À2 is currently needed at the cathode, 6,7 where the oxygen reduction reaction (ORR) takes place:…”

Section: Introductionmentioning

confidence: 99%

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

Stephens

Bondarenko

Grønbjerg

et al. 2012

Energy Environ. Sci.

1,088

1,024

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The high cost of low temperature fuel cells is to a large part dictated by the high loading of Pt required to catalyse the oxygen reduction reaction (ORR). Arguably the most viable route to decrease the Pt loading, and to hence commercialise these devices, is to improve the ORR activity of Pt by alloying it with other metals. In this perspective paper we provide an overview of the fundamentals underlying the reduction of oxygen on platinum and its alloys. We also report the ORR activity of Pt 5 La for the first time, which shows a 3.5-to 4.5-fold improvement in activity over Pt in the range 0.9 to 0.87 V, respectively. We employ angle resolved X-ray photoelectron spectroscopy and density functional theory calculations to understand the activity of Pt 5 La.

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“…A major challenge that hinders the commercialization of PEMFCs is the development of active, cost-effective, and robust catalysts for the oxygen reduction reaction (ORR) [2,3]. While the ORR kinetics on high surface area Pt catalyst is still sluggish, intensive researches have focused on the Pt alloyed catalysts, such as PteCo, PteFe, PteNi and PteCu [4e12].…”

Section: Introductionmentioning

confidence: 99%

Facile synthesis of supported Pt–Cu nanoparticles with surface enriched Pt as highly active cathode catalyst for proton exchange membrane fuel cells

Zhang

Liu

et al. 2012

International Journal of Hydrogen Energy

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Electrochemistry and the Future of the Automobile

Cited by 742 publications

References 51 publications

Lithium Oxalate as Capacity and Cycle-Life Enhancer in LNMO/Graphite and LNMO/SiG Full Cells

Lithium Oxalate as Capacity and Cycle-Life Enhancer in LNMO/Graphite and LNMO/SiG Full Cells

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

Facile synthesis of supported Pt–Cu nanoparticles with surface enriched Pt as highly active cathode catalyst for proton exchange membrane fuel cells

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