772,681 research outputs found
Regulating liquid and solid-state electrolytes for solid-phase conversion in Li–S batteries
No full textThe solid-phase conversion mechanism in lithium–sulfur (Li–S) batteries has emerged with many attractive advantages such as avoiding the parasitic “shuttle effect” of soluble polysulfides and allowing lean electrolyte operating conditions. Electrolyte regulation could be a vital strategy for taking full advantage of solid-phase conversion to realize high-energy Li–S batteries. This review aims to provide a comprehensive overview of the role of electrolyte regulation in promoting solid-phase conversion, thereby preparing high-energy Li–S batteries in liquid, quasi-solid-state, and solid-state media. The work introduces the significance and historical development roadmap of solid-phase conversion in Li–S batteries and explores a design strategy for functional electrolytes based on working mechanisms. Furthermore, it outlines the challenges and opportunities in developing modern Li–S batteries governed by solid-phase conversion. We aim to provide insights and design principles for regulating electrolytes to solve the challenges presented in Li–S batteries, and we hope to provide readers with guidelines for the development and utilization of high-energy Li–S batteries.No Full Tex
Multifunctional Cellulose Nanocrystals as a High-Efficient Polysulfide Stopper for Practical Li–S Batteries
No full textBecause of the severe shuttle effect of polysulfides, achieving durable Li-S batteries is still a great challenge, especially under practical operation conditions including the high sulfur content, high loading, and high operation temperature. Herein, for the first time, low-cost, eco-friendly, and hydrophilic cellulose nanocrystals (CNCs) are proposed as a multifunctional polysulfide stopper for Li-S batteries with high performance. CNCs display an intrinsically high aspect ratio and a large surface area and contain a large amount of hydroxyl groups offering a facile platform for chemical interactions. Density functional theory calculations suggest that the electron-rich functional groups on CNCs deliver robust binding energies with polysulfides. In this work, CNCs not only firmly confine sulfur and polysulfides in the cathode as a robust binder, but also further hinder polysulfide shuttling to the Li anode as a polysulfide stopper on a separator. Consequently, the as-prepared Li-S batteries demonstrate outstanding cycling performance even under the conditions of high sulfur content of 90 wt % (63 wt % in the cathode), high loading of 8.5 mg cm-2, and high temperature of 60 °C. These results sufficiently demonstrate that CNCs have significant application potential in Li-S battery technologies.No Full Tex
Powering 10-Ah-level Li-S pouch cell via a smart “skin”
No full textDespite the significant advantages of lithium-sulfur (Li-S) batteries over conventional lithium-ion batteries (LIBs), the practical usefulness of current Ah-level Li-S pouch cells is unsatisfactory, mainly because of the limited electrochemical performance and potential fire risk issues. In a recent study published in Matter, Wei et al. incorporated an ion-selective “skin” into 10-Ah-level Li-S cells and achieved an energy density of 412.7 Wh kg−1 with a low electrolyte/S ratio of 2.6 and an excess Li of 1.43.No Full Tex
Accelerating S↔Li2S Reactions in Li–S Batteries through Activation of S/Li2S with a Bifunctional Semiquinone Catalyst
No full textThe reaction rate bottleneck during interconversion between insulating S8 (S) and Li2S fundamentally leads to incomplete conversion and restricted lifespan of Li−S battery, especially under high S loading and lean electrolyte conditions. Herein, we demonstrate a new catalytic chemistry: soluble semiquinone, 2-tertbutyl-semianthraquinone lithium (Li+TBAQ⋅−), as both e-/Li+ donor and acceptor for simultaneous S reduction and Li2S oxidation. The efficient activation of S and Li2S by Li+TBAQ⋅− in the initial discharging/charging state maximizes the amount of soluble lithium polysulfide, thereby substantially improve the rate of solid–liquid-solid reaction by promoting long-range electron transfer. With in situ Raman spectra and theoretical calculations, we reveal that the activation of S/Li2S is the rate-limiting step for effective S utilization under high S loading and low E/S ratio. Beyond that, the S activation ratio is firstly proposed as an accurate indicator to quantitatively evaluate the reaction rate. As a result, the Li−S batteries with Li+TBAQ⋅− deliver superior cycling performance and over 5 times higher S utilization ratio at high S loading of 7.0 mg cm−2 and a current rate of 1 C compared to those without Li+TBAQ⋅−. We hope this study contributes to the fundamental understanding of S redox chemical and inspires the design of efficient catalysis for advanced Li−S batteries.No Full Tex
Iron hexadecafluorophthalocyanine nanoparticle/porous carbon composites as cathode materials for Li-S batteries
Get PDFThe shuttle behavior and sluggish conversion kinetics of polysulfides (LiPSs) significantly hinder sulfur utilization and cycle stability of lithium–sulfur (Li–S) batteries. Herein, iron hexadecafluorophthalocyanine (FePcF16) nanoparticles were in situ tailored on oxidized apple pomace carbon (OAPC) with a 3D porous structure to construct a high-performance FePcF16/OAPC sulfur host for advanced Li–S batteries. The designed FePcF16 nanoparticles have strong adsorption and catalytic conversion capabilities, which can reduce the redox reaction energy barrier, accelerate the conversion rate, and inhibit the LiPS shuttle. Meanwhile, the unique porous structure of OAPC effectively realizes the sulfur accommodation and rapid transport of substances. The average capacities of batteries with FePcF16/OAPC were 926.83, 847.11, and 782.63 mA h/g after 500 cycles at 1, 2, and 3C current densities, with capacity decay rates of only 0.020%, 0.031%, and 0.043% per cycle, respectively. Furthermore, it delivers favorable cycling stability at a sulfur load of 4.32 mg/cm2.This work was supported by the National Natural Science Foundation of China (Nos. 52073166, 52172049, U22A20144) and the Shaanxi Natural Science Foundation of China (No. 2019JLM-3).Peer reviewe
Corrigendum to “Reliability assessment of generic geared wind turbines by GTST-MLD model and Monte Carlo simulation” (Renewable Energy (2015) 83 (222–233), (S0960148115003158), (10.1016/j.renene.2015.04.035))
No full textThe authors regret that the Order of Authors in this article published in November 2015 is incorrect. Thus, the objective of this Corrigendum is to re-establish the originally agreed Order of Authors, as described below. Order of Authors from published Article: Yan-Fu Li, PhD; Sebastien Valla; Enrico Zio, PhD. Corrected Order of Authors to implement with this Corrigendum: Sebastien Valla, Yan-Fu Li, PhD; Enrico Zio, PhD. The Corresponding author to contact for these changes are the Primary Author, Sebastien Valla (email below). The authors would like to apologise for any inconvenience caused
Lithium salts for advanced lithium batteries: Li-metal, Li-O2, and Li-S
Get PDFPresently lithium hexafluorophosphate (LiPF6) is the dominant Li-salt used in commercial rechargeable lithium-ion batteries (LIBs) based on a graphite anode and a 3-4 V cathode material. While LiPF6 is not the ideal Li-salt for every important electrolyte property, it has a uniquely suitable combination of properties (temperature range, passivation, conductivity, etc.) rendering it the overall best Li-salt for LIBs. However, this may not necessarily be true for other types of Li-based batteries. Indeed, next generation batteries, for example lithium-metal (Li-metal), lithium-oxygen (Li-O2), and lithium-sulfur (Li-S), require a re-evaluation of Li-salts due to the different electrochemical and chemical reactions and conditions within such cells. This review explores the critical role Li-salts play in ensuring in these batteries viability
Tailoring Li6PS5BR ionic conductivity and understanding of its role in cathode mixtures for high performance all-solid-state Li-S batteries
No full textThe ultrafast ionic conductivity of Li 6 PS 5 Br, which is higher than 1 mS cm -1 at room temperature, makes it an attractive candidate electrolyte for the all-solid-state Li-S battery. A simple synthesis route with an easy scale up process is critical for practical applications. In this work, the highest room temperature ionic conductivity (2.58 × 10 -3 S cm -1 ) of Li 6 PS 5 Br is obtained by an optimal annealing temperature in a simple solid-state reaction method. Neutron diffraction and XRD show that the origin of the highest ionic conductivity is due to the higher purity, smaller mean lithium ion jumps and the optimal Br ordering over 4a and 4c sites. All-solid-state Li-S batteries using a S-C composite cathode in combination with the optimized Li 6 PS 5 Br electrolyte and Li-In anode show high (dis)charge capacities. Different cycling modes (charge-discharge and discharge-charge) reveal that the capacity of the S-C-Li 6 PS 5 Br/Li 6 PS 5 Br/Li-In battery arises from both the active S-C composite and the Li 6 PS 5 Br in the cathode mixture. The contribution of the latter is verified from all-solid-state batteries using Li 6 PS 5 Br and its analogues as active materials. Ex situ XRD and electrochemical performance results show that the contribution of capacity from Li 6 PS 5 Br in the cathode mixture may be associated with the decomposition product Li 2 S, while the Li 6 PS 5 Br in the bulk solid electrolyte layer is stable during cycling. Accepted Author ManuscriptRST/Storage of Electrochemical EnergyRST/Neutron and Positron Methods in Material
Self-rolled-up membrane (S-RuM) capacitors and filters for radio frequency communication
Get PDFSelf-rolled-up membrane (S-RuM) is a novel technology to build precisely controllable three- dimensional (3D) micro-structures. This technology finds wide applications in passive electronics, photonics, and neural interfaces, and achieves great device size reduction and performance enhancement. For passive electronics, devices based on S-RuM utilize electromagnetic energy well- confined in the device tubular cavity with extremely high efficiency, and break the footprint and parasitic effect limit set by conventional planar devices. S-RuM inductors and capacitors can reach self- resonant frequency up to 60 GHz, Q factor up to 80, and with footprint one hundredth that of the state- of-the-art 2D counterparts. This thesis illustrates the working mechanism of S-RuM technology first, and then introduces S-RuM passive electronic devices for radio frequency (RF) application. Current approaches to improve RF passive device performance are discussed. Designs of capacitors and filters based on S-RuM are demonstrated, followed by simulation and lab measurement results. Challenges associated with S-RuM passive electronics are addressed and solutions are proposed. Future work and potential wearable device applications are summarized.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2019-12-01The student, Moyang Li, accepted the attached license on 2017-12-15 at 09:32.The student, Moyang Li, submitted this Thesis for approval on 2017-12-15 at 09:45.This Thesis was approved for publication on 2017-12-15 at 09:53.DSpace SAF Submission Ingestion Package generated from Vireo submission #11992 on 2018-03-13 at 10:38:29Made available in DSpace on 2018-03-13T17:35:58Z (GMT). No. of bitstreams: 2
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DNA-Guided Li<sub>2</sub>S Nanostructure Deposition for High-Sulfur-Loaded Li–S Batteries
No full textThe low areal capacity caused by low sulfur loading (<2.0
mg
cm–2) and the poor sulfur utilization due to the
insulating Li2S layer covering the cathode always limit
the practical applications of lithium–sulfur batteries (Li–S
batteries). Deoxyribonucleic acid (DNA)-controlled nucleation and
growth of Li2S in the Li–S system were first studied
in this work. The negatively charged sugar-phosphate backbone of DNA
could attract Li+ ions and allow crystalline Li2S to grow along the DNA chains. The electrodeposition of Li2S with a unique three-dimensional nanostructure during the polysulfide
conversion and deposition process was realized, which can not only
boost electron and ion transport but also expose and retain more active
sites in the cathode. A Li–S battery with ultrahigh sulfur
loading of 10 mg cm–2 and a low electrolyte/sulfur
ratio of 6.08 delivered a high areal capacity of 8.1 mA h cm–2, which is more than 2 times that of commercial Li-ion batteries,
demonstrating a great enhancement of the Li–S battery compared
to other studies. Therefore, this study provides an effective strategy
of DNA-guided 3D Li2S deposition for achieving high-sulfur-loading
Li–S batteries
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