Revisiting the Role of Polysulfides in Lithium-Sulfur Batteries (original) (raw)
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Electrocatalysis of Lithium Polysulfides
Lithium Sulfur (Li/S) chemistries are amongst the most promising next-generation battery technologies due to their high theoretical energy density. However, the detrimental effects of their intermediate byproducts, polysulfides (PS), have to be resolved to realize these theoretical performance limits. Confined approaches on using porous carbons to entrap PS have yielded limited success. In this study, we deviate from the prevalent approach by introducing catalysis concept in Li/S battery configuration. Engineered current collectors were found to be catalytically active towards PS, thereby eliminating the need for carbon matrix and their processing obligatory binders, additives and solvents. We reveal substantial enhancement in electrochemical performance and corroborate our findings using a detailed experimental parametric study involving variation of several kinetic parameters such as surface area, temperature, current rate and concentration of PS. The resultant novel battery configuration delivered a discharge capacity of 700 mAh g 21 with the two dimensional (2D) planar Ni current collectors and an enhancement in the capacity up to 900 mAh g 21 has been realized using the engineered three dimensional (3D) current collectors. The battery capacity has been tested for stability over 100 cycles of charge-discharge. P ast decade has witnessed a renewed interest in development of high energy storage devices, the interest is further bolstered by their potential applications for plug-in hybrid and electric vehicles. Intercalation materials employed in conventional Li-ion batteries impose limitations on the energy density that can be achieved. These shortcomings have stimulated research in alternative chemistries labelled beyond lithium ion batteries 1-5 . Among several re-visited chemistries, rechargeable lithium/sulfur (Li/S) batteries have gained attraction due to their high theoretical capacity of 1675 mAh g 21 of sulfur cathode, wide range of temperature operation and low cost 6-11 . In spite of several research efforts on this subject, key issues related to ''redox shuttle reactions'' between sulfur cathode and Li anode have not been fully addressed yet 12,13 . Poor understanding and lack of control on the series of intermediate lithium polysulfides (PS) are commonly identified problems in all Li/S battery configurations such as solid, liquid and flow cells 9,14-18 . Though the overall redox reaction is primarily driven by the dissolution of lithium polysuflides into the electrolyte, the insulating nature of the polysulfides and its predisposition to corrode the lithium anode results in low charging efficiency, short cycle life and high selfdischarges.
Advances in lithium—sulfur batteries
Materials Science and Engineering: R: Reports, 2017
This review is focused on the state-of-the-art of lithium-sulfur batteries. The great advantage of these energy storage devices in view of their theoretical specific capacity (2500 Wh kg-1 , 2800 Wh L-1 , assuming complete reaction to Li2S) has been the motivation for a huge amount of works. However, these batteries suffer of disadvantages that have restricted their applications such as high electrical resistance, capacity fading, self-discharge, mainly due to the so-called shuttle effect. Strategies have been developed with the recent modifications that have been proposed as a remedy to the shuttle effect, and the insulating nature of the polysulfides. All the elements of the battery are concerned and the solution, as we present herewith, is a combination of modification of the cathode, of the separator, of the electrolyte, including the choice of binder, even though few binder-free architectures have now been proposed.
A Comprehensive Understanding of Lithium–Sulfur Battery Technology
Advanced Functional Materials, 2019
Lithium-sulfur batteries (LSBs) are regarded as a new kind of energy storage device due to their remarkable theoretical energy density. However, some issues, such as the low conductivity and the large volume variation of sulfur, as well as the formation of polysulfides during cycling, are yet to be addressed before LSBs can become an actual reality. Here, presented is a comprehensive overview illustrating the techniques capable of mitigating these undesirable problems together with the electrochemical performances associated to the different proposed solutions. In particular, the analysis is organized by separately addressing cathode, anode, separator, and electrolyte. Furthermore, to better understand the chemistry and failure mechanisms of LSBs, important characterization techniques applied to energy storage systems are reviewed. Similarly, considerations on the theoretical approaches used in the energy storage field are provided, as they can become the key tool for the design of the next generation LSBs. Afterward, the state of the art of LSBs technology is presented from a geopolitical perspective by comparing the results achieved in this field by the main world actors, namely Asia, North America, and Europe. Finally, this review is concluded with the application status of LSBs technology, and its prospects are offered.
ACS nano, 2017
Lithium-sulfur batteries, notable for high theoretical energy density, environmental benignity, and low cost, hold great potential for next-generation energy storage. Polysulfides, the intermediates generated during cycling, may shuttle between electrodes, compromising the energy density and cycling life. We report herein a class of regenerative polysulfide-scavenging layers (RSL), which effectively immobilize and regenerate polysulfides, especially for electrodes with high sulfur loadings (e.g., 6 mg cm(-2)). The resulting cells exhibit high gravimetric energy density of 365 Wh kg(-1), initial areal capacity of 7.94 mAh cm(-2), low self-discharge rate of 2.45% after resting for 3 days, and dramatically prolonged cycling life. Such blocking effects have been thoroughly investigated and correlated with the work functions of the oxides as well as their bond energies with polysulfides. This work offers not only a class of RSL to mitigate shuttling effect but also a quantified design fr...
Journal of Energy Chemistry, 2019
Lithium-sulfur batteries (LSBs) are promising alternative energy storage devices to the commercial lithium-ion batteries. However, the LSBs have several limitations including the low electronic conductivity of sulfur (5 × 10 −30 S cm −1), associated lithium polysulfides (PSs), and their migration from the cathode to the anode. In this study, a separator coated with a Ketjen black (KB)/Nafion composite was used in an LSB with a sulfur loading up to 7.88 mg cm −2 to mitigate the PS migration. A minimum specific capacity (C s) loss of 0.06% was obtained at 0.2 Crate at a high sulfur loading of 4.39 mg cm −2. Furthermore, an initial areal capacity up to 6.70 mA h cm −2 was obtained at a sulfur loading of 7.88 mg cm −2. The low C s loss and high areal capacity associated with the high sulfur loading are attributed to the large surface area of the KB and sulfonate group (SO 3 −) of Nafion, respectively, which could physically and chemically trap the PSs.
Ameliorating the energy storage performance of lithium sulfur batteries via sulfur intercalated
Energy&fuels , 2022
Theoretically, batteries based on lithium−sulfur have a high energy density. However, involuntary dendritic growth at the anode and poor high- loading performance at the cathode have plagued the practical implementation of Li−S batteries. However, capacity fading occurs due to the lithium polysulfide shuttle effect, while its redox nature should also be improved. Therefore, titanium carbide MXene (Ti3C2Tx MXene) with a layered-stacked structure is used as an ideal host material for the sulfur cathode, with the sulfur content affecting the electrochemical performance of the composites consisting of sulfur nanoparticles and Ti3C2Tx MXene. When the reactant has a 1:4 MXene-to-sulfur mass ratio, it gorges the layered-stacked structure equally. Additionally, the surface terminal groups exhibit a high degree of LiPSn adsorption. As a result, the S@MXene composite (68 wt %) demonstrated a superior cycling performance of 1034 mAh g−1 even after 100 cycles and an initial reversible capacity of 1231 mAh g−1 at 0.5C, respectively. This study establishes a platform for developing improved cathode materials based on sulfur for lithium−sulfur batteries.
Approaches to Combat the Polysulfide Shuttle Phenomenon in Li–S Battery Technology
Batteries
Lithium–sulfur battery (LSB) technology has tremendous prospects to substitute lithium-ion battery (LIB) technology due to its high energy density. However, the escaping of polysulfide intermediates (produced during the redox reaction process) from the cathode structure is the primary reason for rapid capacity fading. Suppressing the polysulfide shuttle (PSS) is a viable solution for this technology to move closer to commercialization and supersede the established LIB technology. In this review, we have analyzed the challenges faced by LSBs and outlined current methods and materials used to address these problems. We conclude that in order to further pioneer LSBs, it is necessary to address these essential features of the sulfur cathode: superior electrical conductivity to ensure faster redox reaction kinetics and high discharge capacity, high pore volume of the cathode host to maximize sulfur loading/utilization, and polar PSS-resistive materials to anchor and suppress the migratio...