Explore the vast range of titles available.

All-climate temperature operation capability and increased energy density have been recognized as two crucial targets, but they are rarely achieved together in rechargeable lithium (Li) batteries. Herein, we demonstrate an electrolyte system by using monodentate dibutyl ether with both low melting and high boiling points as the sole solvent. Its weak solvation endows an aggregate solvation structure and low solubility toward polysulfide species in a relatively low electrolyte concentration (2 mol L−1). These features were found to be vital in avoiding dendrite growth and enabling Li metal Coulombic efficiencies of 99.0%, 98.2%, and 98.7% at 23 °C, −40 °C, and 50 °C, respectively. Pouch cells employing thin Li metal (50 μm) and high-loading sulfurized polyacrylonitrile (3.3 mAh cm−2) cathodes (negative-to-positive capacity ratio = 2) output 87.5% and 115.9% of their room temperature capacity at −40 °C and 50°C, respectively. This work provides solvent-based design criteria for a wide temperature range Li-sulfur pouch cells.

Lithium‐ion batteries (LIBs) are undoubtedly the current working‐horse in almost all portable electronic devices, electric vehicles, and even large‐scale stationary energy storage. Given the problems faced by LIBs, a big question arises as to which battery(ies) would be the “Beyond LIBs” batteries. Among the front‐runners, lithium‐sulfur batteries (LSBs) have been extensively pursued owing to their intrinsically high energy density and extremely low cost. Despite the steady and sometimes exciting progress reported on sulfur chemistry and cell performance at laboratory scales over the past decade, one of the major bottlenecks is the poor cyclability. In this perspective, we examine the key challenges and opportunities faced by LSBs, as well as approaches at the materials, electrode/electrolyte and cell integration levels that can be taken to transform LSBs from a front‐runner to a real leading champion in the pursuit of the “Beyond LIBs”. While the key new mechanistic insights are very important, we propose a set of the near‐future research directions for both the liquid and solid state LSBs, where the currently on‐going parallel pursuits of both liquid and solid LSBs will be converging. The “liquid current” will gradually be taken over by “solid future” in the expected LSBs commercialization in the coming decade. Lithium‐sulfur batteries: a potentially leading champion in the “Beyond LIBs” era, where the all‐solid‐state batteries shall be the holy grail.

Lithium sulfide (Li2S) is a promising cathode for a practical lithium‐sulfur battery as it can be coupled with various safe lithium‐free anodes. However, the high activation potential (>3.5 V) together with the shuttling of lithium polysulfides (LiPSs) bottleneck its practical uses. We are trying to present a catalysis solution to solve both problems simultaneously, specially with twinborn heterostructure to shoot off the trouble in interfacial contact between two solids, catalyst and Li2S. As a typical example, a Co9S8/Li2S heterostructure is reported here as a novel self‐catalytic cathode through a co‐recrystallization followed by a one‐step carbothermic conversion. Co9S8 as the catalyst effectively lowers the Li2S activation potential (<2.4 V) due to fully integrated and contacted interfaces and consistently promotes the conversion of LiPSs to suppress the shuttling. The obtained freestanding cathode of Co9S8/Li2S heterostructures encapsulated in three‐dimensional graphene shows a high capacity, reaching 92.6% of Li2S theoretical capacity, high rate performance (739 mAh g−1 at 2 C), and a low capacity fading (0.039% per cycle at 1 C over 900 cycles). Even under a high Li2S loading of 12 mg cm−2 and a low E/S ratio of 5μLmgLi2S−1, 86% of theoretical capacity can be utilized. A twinborn heterostructure of Co9S8 catalyst wrapped by Li2S was prepared by co‐recrystallization and carbothermic reduction of salt precursors. This structure maximizes the solid–solid contact interfaces between them, lowering the overpotential of Li2S oxidation and achieving the high Li2S utilization and good cycling stability in the cells coupled with Li metal anode and Li metal free anodes (graphite and Si/C).

It is a long‐standing issue that the sluggish polysulfide conversion and adverse shuttling effects impede the development of lithium‐sulfur (Li‐S) batteries with high energy density and cycling stability, which necessitate the exploration of new electrocatalysts to facilitate the practical applications of Li‐S batteries. Herein, a single‐phase high‐entropy stabilized oxide (Ni0.2Co0.2Cu0.2Mg0.2Zn0.2)O (HEO850) is successfully prepared through a novel low‐temperature annealing strategy from a self‐sacrificing metal–organic frameworks (MOFs) template and then integrated into the sulfur host, where it functions as both the catalytic converter and chemical inhibitor towards the shuttle species. Furthermore, the synergistic contribution of randomly dispersed metal elements and the exposure of affluent active sites enable the chemical encapsulation of soluble polysulfides and accelerate conversion kinetics. The HEO850/S/KB cathode (KB: ketjen black; sulfur content: 70 wt.%) delivers a substantially higher initial specific discharge capacity of ~1244 mAh g−1 in comparison to MEO/S/KB (MEO: medium entropy oxide; ~980 mAh g−1), LEO/S/KB (LEO: low entropy oxide; ~908 mAh g−1), and routine S/KB cathodes (~966 mAh g−1), which is well retained at ~784 mAh g−1 after 800 cycles at 0.5 C with a low capacity decay rate of ~0.043% per cycle. Moreover, when the HEO850/S/KB cathode is processed with a high areal sulfur loading (~4.4 mg cm−2), the resulting Li‐S battery also performs well, with a high initial specific capacity of ~1044 mAh g−1 at 0.1 C and 85% capacity retention after 100 cycles. This study highlights the potential application of HEOs in enhancing the performance of Li‐S batteries and provides a novel strategy in synthesizing the HEOs at a relatively low annealing temperature for various energy conversion and storage applications. A single‐phase high‐entropy stabilized oxide (Ni0.2Co0.2Cu0.2Mg0.2Zn0.2)O (HEO850) is successfully prepared through a novel low‐temperature annealing strategy from a self‐sacrificing metal–organic frameworks (MOFs) template and then integrated into the sulfur host as both the catalytic converter and chemical inhibitor towards the shuttle species. The HEO850/S/KB cathode delivers a substantially higher initial specific discharge capacity of ~1244 mAh g−1. Impressively, the HEO850/S/KB cathode with a high areal sulfur loading (~4.4 mg cm−2) could result in an initial specific capacity of ~1044 mAh g−1 at 0.1 C and 85% capacity retention after 100 cycles.

With the advantages of superior energy density, lithium‐sulfur batteries (LSBs) have been considered as one of the promising next‐generation batteries. However, some key issues, such as the shuttle effect of the intermediate lithium polysulfides, poor conductivity of the sulfur, Li2S and Li2S2, and huge volume variation during charge/discharge process, have hindered its development. In this respect, a variety of nanomaterials have been used to overcome the above‐mentioned defects. Among them, two‐dimensional (2D) nanomaterials present unique merits for enhancing the electrochemical performance of LSBs owing to their unique structural properties. Nevertheless, the variation of 2D nanomaterials used in LSBs is rarely discussed. Herein, this work systematically reviews the state‐of‐the‐art progress in LSB cathode development through 2D materials such as graphene, MXenes, 2D compounds, and so forth. With a comprehensive analysis, the challenges and perspectives for 2D nanomaterials in LSBs application are proposed and discussed. Two‐dimensional nanomaterials, a new class of sheet‐like nanomaterials, play a critical role in cathode for lithium‐sulfur batteries owing to their tremendous physical and electrochemical properties. In this review, the state‐of‐the‐art progress in two‐dimensional nanomaterials‐based cathodes for lithium‐sulfur batteries is summarized from different perspectives. With a comprehensive review and discussion, challenges and insights to further development of two‐dimensional nanomaterials‐based cathodes for lithium‐sulfur batteries are proposed.

For lithium‐sulfur batteries (Li‐S batteries), a high‐content electrolyte typically can exacerbate the shuttle effect, while a lean electrolyte may lead to decreased Li‐ion conductivity and reduced catalytic conversion efficiency, so achieving an appropriate electrolyte‐to‐sulfur ratio (E/S ratio) is essential for improving the battery cycling efficiency. A quasi‐solid electrolyte (COF‐SH@PVDF‐HFP) with strong adsorption and high catalytic conversion was constructed for in situ covalent organic framework (COF) growth on highly polarized polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) fibers. COF‐SH@PVDF‐HFP enables efficient Li‐ion conductivity with low‐content liquid electrolyte and effectively suppresses the shuttle effect. The results based on in situ Fourier‐transform infrared, in situ Raman, UV–Vis, X‐ray photoelectron, and density functional theory calculations confirmed the high catalytic conversion of COF‐SH layer containing sulfhydryl and imine groups for the lithium polysulfides. Lithium plating/stripping tests based on Li/COF‐SH@PVDF‐HFP/Li show excellent lithium compatibility (5 mAh cm−2 for 1400 h). The assembled Li‐S battery exhibits excellent rate (2 C 688.7 mAh g−1) and cycle performance (at 2 C of 568.8 mAh g−1 with a capacity retention of 77.3% after 800 cycles). This is the first report to improve the cycling stability of quasi‐solid‐state Li‐S batteries by reducing both the E/S ratio and the designing strategy of sulfhydryl‐functionalized COF for quasi‐solid electrolytes. This process opens up the possibility of the high performance of solid‐state Li‐S batteries. The sulfhydryl‐covalent organic framework functionalized polyvinylidene fluoride‐hexafluoropropylene as a quasi‐solid electrolyte enhances the chemical affinity of polysulfides in lithium‐sulfur batteries, accelerating the conversion reaction kinetics, improving the catalytic conversion efficiency of polysulfides and the utilization rate of active materials in lithium‐sulfur batteries, and providing a potential reference for the electrolyte design of high‐loading and high‐performance lithium‐sulfur batteries.

Lithium‐sulfur batteries (LSBs) have garnered attention from both academia and industry because they can achieve high energy densities (>400 Wh kg–1), which are difficult to achieve in commercially available lithium‐ion batteries. As a preparation step for practically utilizing LSBs, there is a problem, wherein battery cycle life rapidly reduces as the loading level of the sulfur cathode increases and the electrode area expands. In this study, a separator coated with boehmite on both sides of polyethylene (hereinafter denoted as boehmite separator) is incorporated into a high‐loading Li‐S pouch battery to suppress sudden capacity drops and achieve a longer cycle life. We explore a phenomenon by which inequality is generated in regions where an electrochemical reaction occurs in the sulfur cathode during the discharging and charging of a high‐capacity Li‐S pouch battery. The boehmite separator inhibits the accumulation of sulfur‐related species on the surface of the sulfur cathode to induce an even reaction across the entire cathode and suppresses the degradation of the Li metal anode, allowing the pouch battery with an areal capacity of 8 mAh cm–2 to operate stably for 300 cycles. These results demonstrate the importance of customizing separators for the practical use of LSBs. Pouch‐type lithium‐sulfur batteries with a high areal capacity of more than 8 mAh cm–2 are developed by using a three‐dimensional compact sulfur cathode and a separator coated with boehmite on both sides of polyethylene which improves the uniformity of the regions at which the electrochemical reactions take place (on both high loading cathode and lithium metal anode).

Lithium–sulfur (Li ‒S) battery has been considered as one of the most promising future batteries owing to the high theoretical energy density (2600 W·h·kg −1) and the usage of the inexpensive active materials (elemental sulfur). The recent progress in fundamental research and engineering of the Li ‒S battery, involved in electrode, electrolyte, membrane, binder, and current collector, has greatly promoted the performance of Li‒S batteries from the laboratory level to the approaching practical level. However, the safety concerns still deserve attention in the following application stage. This review focuses on the development of the electrolyte for Li‒S batteries from liquid state to solid state. Some problems and the corresponding solutions are emphasized, such as the soluble lithium polysulfides migration, ionic conductivity of electrolyte, the interface contact between electrolyte and electrode, and the reaction kinetics. Moreover, future perspectives of the safe and high-performance Li‒S batteries are also introduced.

Electrocatalysts play key roles in improving the performance of lithium sulfur (Li‐S) batteries. Here, the electrocatalytic activity of different CoSe2 surfaces for the polysulfide redox reactions in Li‐S batteries, by means of first‐principle calculations is considered. The authors demonstrate that there are obvious differences in surface energy (0.7–2.34 J m−2), adsorption energy for lithium polysulfides (LiPSs) (1.2–3.5 eV), Gibbs free energy of sulfur reduction reaction (SRR) (0.37–1.16 eV), and Li2S decomposition barrier (0.15–0.94 eV) among different CoSe2 surfaces, and thus lead to the different electrocatalytic activity for different CoSe2 surface. The stoichiometric CoSe2 surface with high surface energy, such as the (001) surface, tends to have stronger adsorption energy and larger SRR Gibbs free energy for LiPSs. The surface electron states are mainly dominated by p–d hybridization orbitals and the p‐band center is vital for the surface electrocatalytic properties. Such surface‐dependent mechanism may shed light on the design of sulfur host materials for high‐performance Li‐S batteries. Density functional theory is a powerful tool for theoretically designing and understanding lithium‐sulfur battery materials on an atomic scale. The different catalytic activities caused by the surface effects are very charming. The surface‐dependent electrocatalytic effect of the sulfur reduction reaction of CoSe2 may shed light on the design of sulfur host materials for high‐performance lithium‐sulfur batteries.