Effect of imidazolium cation on cycle life characteristics of secondary lithium–sulfur cells using liquid electrolytes

et al. 2014

J. Electrochem. Soc.

Self Cite

This work presents a new insight into the reduction mechanism of solid sulfur during the first step of cell discharge, that is, a 2.4 V plateau in Li-S batteries, by testing a specially designed cell with the solid sulfur electrically isolated from the carbon cathode and comparing it with a conventional cell. Importantly, the cell with the electrically isolated sulfur particles confined between two separators shows very normal operation even during the first cycle and provides the same result as a conventional cell after several cycles. Based on the controlled potentiostatic and galvanostatic experiments, we propose a reasonable reaction route: a portion of the electrically isolated solid sulfur (S 8 ) is dissolved in the electrolyte solution to form sulfur molecules, which can be electrochemically reduced to polysulfides on the carbon surface.

mentioning

confidence: 99%

Electrochemical Reduction Mechanism of Sulfur Particles Electrically Isolated from Carbon Cathodes of Lithium-Sulfur Cells

Koh

Park

et al. 2014

J. Electrochem. Soc.

Self Cite

“…Although, the cells delivered an initial discharge capacity of 1055 mAh g −1 in its first cycle an abrupt decrease in discharge capacity (about 770 mAh g −1 ) was found after a few cycles. The effect of imidazolium cation on the cycle life of Li-S batteries has been analyzed by Kim et al (2007). Wang and Byon (2013) designed a new ionic liquid-based organic electrolyte, which swaps solubility and diffusion rate of polysulfides by a combination of 1,2-dimethoxyethane and highly viscous N -methyl-Npropylpiperidinium bis(trifluoromethane sulfonyl) imide (PP13-TFSI).…”

Section: Ionic Liquids As Electrolytesmentioning

confidence: 99%

Efficient Electrolytes for Lithiumâ€“Sulfur Batteries

Angulakshmi

Stephan

2015

Front. Energy Res.

This review article mainly encompasses on the state-of-the-art electrolytes for lithiumsulfur batteries. Different strategies have been employed to address the issues of lithiumsulfur batteries across the world. One among them is identification of electrolytes and optimization of their properties for the applications in lithium-sulfur batteries. The electrolytes for lithium-sulfur batteries are broadly classified as (i) non-aqueous liquid electrolytes, (ii) ionic liquids, (iii) solid polymer, and (iv) glass-ceramic electrolytes. This article presents the properties, advantages, and limitations of each type of electrolytes. Also, the importance of electrolyte additives on the electrochemical performance of Li-S cells is discussed.

“…Lithium-sulfur batteries have a much higher specific capacity (1,675 mAh/g) and energy density (2,600 Wh/kg) than conventional lithium ion batteries [1][2][3][4][5][6]. However, lithium sulfur batteries are difficult to commercialize, because the lithium metal used as the anode is prone to dendrite growth and explosiveness.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Properties of Lithium Sulfur Battery with Silicon Anodes Lithiated by Direct Contact Method

Jeong

Journal of Electrochemical Science and Technology

2016

It is hard to employ the carbon materials or the lithium metal foil for the anode of lithium sulfur batteries because of the poor passivation in ether-based electrolytes and the formation of lithium dendrites, respectively. Herein, we investigated the electrochemical characteristics of lithium sulfur batteries with lithiated silicon anode in the liquid electrolytes based on ether solvents. The silicon anodes were lithiated by direct contact with lithium foil in a 1M lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) solution in 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) at a volume ratio of 1:1. They were readily lithiated up to ~40% of their theoretical capacity with a 30 min contact time. In particular, the carbon mesh reported in our previous work was employed in order to maximize the performance by capturing the dissolved polysulfide in sulfur cathode. The reversible specific capacity of the lithiated silicon-sulfur batteries with carbon mesh was 1,129 mAh/g during the first cycle, and was maintained at 297 mAh/g even after 50 cycles at 0.2 C, without any problems of poor passivation or lithium dendrite formation.