282,656 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
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
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
Magnèli phase TiOx in carbon as highly efficient cathode for Li/S batteries
No full textNatural abundance of elemental sulfur in the Earth’s crust make Li-S technology as an attractive low cost alternative to Li-ion batteries. Some of setbacks in Li-S technology include: (i) a low degree of sulfur utilization, (ii) quick capacity fading during cycling, (iii) relatively poor rate capability and (iv) a low Coulombic efficiency [1-2]. These limitations mainly arise because of the low conductivity of S8 (5 × 10−18 S cm−1), the solubility of polysulfide intermediates, shuttling of dissolved polysulfides, and a general lack of morphological restoration of the sulfur-containing host material during long term cycling [2]. In this work, we demonstrate integration of multiple design strategies to form a cost effective and sustainable sulfur-containing electrode of carbon and Magnéli phase TinO2n-1, that offers exceptional long life and good rate performance with high S loading for Li-S batteries. Electrically conductive Magnéli phase nanoparticle-loaded carbon matrices (TinO2n-1@C/S) were synthesized by simple heat treatment of the mixture of TiO2 nanotubes and polyvinyl alcohol (PVA) in inert environment. The approach also suppresses the sintering and grain growth in TinO2n-1 nanoparticles ensuring high surface area for LiPS docking that mitigates shuttling effect for high capacity Li/S batteries. Sulfur is introduced into the carbon matrix by a simple thermal infusion process, allowing a high areal sulfur loading (>2.3 mg cm-2) with effective LiPS adsorption. The cells were efficiently charged and discharged for 1000 cycles up to 1 C, even for low E/S ratio. This study also demonstrates how physical entrapment of porous carbon in addition to the chemical binding capability of several Magnéli phase oxides contribute synergistically to realize long cycle life Li-S batteries. [1] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J. M. Tarascon, Nat Mater 2012, 11, 19.
[2] N. S. Choi, Z. H. Chen, S. A. Freunberger, X. L. Ji, Y. K. Sun, K. Amine, G. Yushin, L. F. Nazar, J. Cho, P. G. Bruce, Angew Chem Int Edit 2012, 51, 9994
A porous nitrogen and phosphorous dual doped graphene blocking layer for high performance Li-S batteries
No full textConductive confinement of sulfur and polysulfide via carbonaceous blocking layers can simultaneously address the low conductivity, volume expansion of sulfur during charge/discharge process and polysulfides shuttling effect in lithium-sulfur (Li-S) batteries. Herein, conductive and porous nitrogen and phosphorus dual doped graphene (p-NP-G) blocking layer is prepared via a thermal annealing and subsequent hydrothermal reaction route. The doping levels of N and P in p-NP-G measured by the X-ray photoelectron spectroscopy are ca. 4.38% and ca. 1.93 %, respectively. The dual doped blocking layer exhibits higher conductivity than N or P single doped blocking layer. More importantly, the density function theory (DFT) calculation demonstrates that P atoms and -P-O groups in the p-NP-G layer offer stronger adsorption to polysulfides than the N species. The electrochemical evaluation results illustrate that the p-NP-G blocking layer could deliver superior initial capacity (1158.3 mA h/g at the current density of 1 C), excellent rate capability (633.7 mA h/g at 2 C), and satisfactory cycling stability (ca. 0.09% capacity decay per cycle), which are better than the N or P single doped graphene. This work suggests that this synergetic combination of conductive and adsorptive confinement strategies induced by the multi-heteroatoms doping scheme is a promising approach for developing high performance Li-S batteries.Griffith Sciences, Griffith School of EnvironmentFull Tex
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
Study of B c + → J / ψ D s + and B c + → J / ψ D s ∗ + decays in pp collisions at s = 13 TeV with the ATLAS detector
No full textAbstract
A study of
B
c
+
→
J
/
ψ
D
s
+
and
B
c
+
→
J
/
ψ
D
s
∗
+
decays using 139 fb−1 of integrated luminosity collected with the ATLAS detector from
s
= 13 TeV pp collisions at the LHC is presented. The ratios of the branching fractions of the two decays to the branching fraction of the
B
c
+
→ J/ψπ+ decay are measured:
B
B
c
+
→
J
/
ψ
D
s
+
/
B
B
c
+
→
J
/
ψπ
+
= 2.76 ± 0.47 and
B
B
c
+
→
J
/
ψ
D
s
∗
+
/
B
B
c
+
→
J
/
ψπ
+
= 5.33 ± 0.96. The ratio of the branching fractions of the two decays is found to be
B
B
c
+
→
J
/
ψ
D
s
∗
+
/
B
B
c
+
→
J
/
ψ
D
s
∗
+
= 1.93 ± 0.26. For the
B
c
+
→
J
/
ψ
D
s
∗
+
decay, the transverse polarization fraction, Γ±±/Γ, is measured to be 0.70 ± 0.11. The reported uncertainties include both the statistical and systematic components added in quadrature. The precision of the measurements exceeds that in all previous studies of these decays. These results supersede those obtained in the earlier ATLAS study of the same decays with
s
= 7 and 8 TeV pp collision data. A comparison with available theoretical predictions for the measured quantities is presented
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
LI C 5.5 m/s
No full textSimulation vs experimental testing output comparison for the Hybrid III head form linear impacts (LI) impact location C 5.5 m/s
LI C 9.3 m/s
No full textSimulation vs experimental testing output comparison for the Hybrid III head form linear impacts (LI) impact location C 9.3 m/s
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