Cathode Kinetics Evaluation in Lean-Electrolyte Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries possess high theoretical specific energy but suffer from lithium polysulfide (LiPS) shuttling and sluggish reaction kinetics. Catalysts in Li-S batteries are deemed as a cornerstone for improving the sluggish kinetics and simultaneously mitigating the LiPS shuttling. Herein, a cost-effective hexagonal close-packed (hcp)-phase Fe-Ni alloy is shown to serve as an efficient electrocatalyst to promote the LiPS conversion reaction in Li-S batteries. Importantly, the electrocatalysis mechanisms of Fe-Ni toward LiPS conversion is thoroughly revealed by coupling electrochemical results and post mortem transmission electron microscopy, X-ray photoelectron spectroscopy, and in situ X-ray diffraction characterization. Benefiting from the good catalytic property, the Fe-Ni alloy enables a long lifespan (over 800 cycles) and high areal capacity (6.1 mA h cm-2) Li-S batteries under lean electrolyte conditions with a high sulfur loading of 6.4 mg cm-2. Impressively, pouch cells fabricated with the Fe-Ni/S cathodes achieve stable cycling performance under practically necessary conditions with a low electrolyte/sulfur (E/S) ratio of 4.5 μL mg-1. This work is expected to design highly efficient, cost-effective electrocatalysts for high-performance Li-S batteries.

As an inexpensive, abundantly available, and environmental-friendly material, sulfur has become one of the most promising positive electrode active materials because of its high theoretical specific capacity (1675 mAh g-1). However, lithium sulfur batteries (Li-S Battery) still have some issues for practical application: the electronically insulating nature of sulfur and its discharge products (Li2S/Li2S2); the dissolution and shuttle effect of lithium polysulfides (LiPSs) in the conventional dioxolane/dimethoxyethane (DOL/DME) electrolyte. In addition, excess amounts of electrolyte that overcompensate for its minimum requirement are necessary for achieving a high specific capacity of sulfur, which severely reduces the energy density of the battery. However, only poor charge/discharge behavior could be obtained when the E/S ratios lower than 5 with the conventional DOL/DME electrolyte.1 In order to overcome the above problems, we have proposed sparingly solvating electrolytes made with lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]) and sulfolane (SL), in which LiPSs have limited solubility to inhibit the LiPS shuttling effect. Moreover, to realize high energy density Li-S batteries, it is essential to reduce the E/S ratio (E/S [μL-electrolyte/mg-sulfur]). Here, we fabricated a pouch cell using the sparingly solvating electrolytes and the cyclability with various E/S ratios was studied.The sparingly solvating electrolytes are [Li(SL)2][TFSA] (Li[TFSA] : SL = 1 : 2) in which a poorly solvating diluent, 1,1,2,2,-tetrafluoroethyl-2,2,3,3,-tetrafluoropropyl ether (HFE), was added at different molar ratios. Sulfur cathodes consisted of sulfur and Ketjen black (KB) at a ratio of 3: 1, which are coated on a carbon-coated aluminum foil with carboxymethylcellulose (CMC) and styrene-butadiene rubber (SBR) binders. Pouch cells, which have laminated structures, were prepared using the sulfur cathode, Li metal anode, and Celgard3501 separator. Constant current charge/discharge tests were carried out at cut-off voltage 1.0-3.3 V and at 30 ℃.There were non-negligible differences in electrochemical performances of Li-S batteries between coin cells and pouch cells. Especially, under lean electrolyte conditions (low E/S), only pouch cells gave reasonable results. A high energy density Li-S cell having higher energy density than 300 Wh/kg was successfully demonstrated. Therefore, fabrication of pouch cell is a necessary step to probe the stability of the electrode and to evaluate the electrochemical performances under different low E/S ratios. Fig. 1 shows the capacity retention of Li-S cells with various E/S ratios. Although the initial discharge capacity was almost the same, being independent of E/S ratios. However, the cycle stability significantly deteriorated with decreasing E/S. An internal short circuit due to the dendrite formation also occurred relatively early when E/S < 5. On the other hand, when E/S> 5, a high capacity could be maintained, and an internal short circuit hardly occurred even at the relatively high current density. In pouch cells, the electrode area is generally much larger than that in coin cells. Therefore, the absolute magnitude of current is much higher. As a result, if side reactions between electrolyte and Li anode occur and current density in the cell becomes inhomogeneous, the current concentration in the cell will leads to the dendrite growth. Considering the reduction of E/S is urgent for practical high energy density of Li-S battery, it is necessary to suppress the side reactions and dendrite growth on the lithium anode. By using ab initio molecular dynamics simulations and operando electrochemical mass spectroscopy together with cryo-STEM-EELS techniques, the side reactions between the electrolyte and Li anode were explored. How to reduce the side reactions will be discussed in detail in the presentation.AcknowledgementsThis study was supported by the Advanced Low Carbon Technology Research and Development Program (ALCA) of the Japan Science and Technology Agency (JST). We also appreciate Dr. Keisuke Shinoda for his kind support for Cryo-STEM-EELS measurement at National Institute for Materials Science (NIMS) Battery Research Platform.

Lithium-sulfur (Li-S) batteries hold great promise as a next-generation energy storage system due to their high theoretical energy density (2600 W h kg-1), surpassing conventional lithium-ion batteries. However, their performance is often limited by the intrinsic transformation of soluble lithium polysulfides (LiPSs) into short-chain insoluble sulfur species (Li2S2/Li2S), which induces significant cell polarization, particularly under lean-electrolyte conditions. Through a galvanic replacement reaction (GRR), enabling precise tailoring of interfacial properties, AgCl-PVP nanocubes (NCs) were synthesized and utilized as sulfur host materials. These materials demonstrated effective entrapment of LiPSs, as confirmed by in situ electrochemical visualization. Furthermore, the AgCl-PVP NCs significantly reduced whole-cell polarization, particularly during the Li2S nucleation step, as validated by galvanostatic intermittent titration technique across the depth of discharge. Under lean-electrolyte conditions (5.6 μL mg-1), the AgCl-PVP NCs cathode exhibited high specific capacity (563.62 mA h g-1 at 0.2 C) with a low-capacity decay rate (1.81% per cycle). These results demonstrate the potential of GRR-engineered nanostructures as sulfur host material for enhancing the electrochemical performance and practical applicability of lean-electrolyte Li-S batteries.

Quasi-solid-state sulfur cathode with ultralean electrolyte via in situ polymerization

Li-S batteries are among the most promising candidates for the next generation rechargeable batteries due to their high energy density, low raw material cost and environmental friendliness [1]. Despite this great potential, the complicated electrochemical process introduces many challenges for Li-S batteries, including low conductivity of both elemental sulfur and end discharge product Li2S, large volume expansion of 80% upon discharge, and unfavorable redox shuttle effect due to soluble nature of intermediate lithium polysulfide LiPS [2,3]. Although Li-S batteries possess a high theoretical cathode specific capacity of 1,672 mAh g-1, the energy density of practical Li-S batteries is much smaller and depends on electrolyte/sulfur (E/S in mL g-1) ratio. From previous works, successful operation of Li-S batteries under lean electrolyte conditions can be challenging, especially in the case when the solubility of LiPS sets an upper bound for polysulfide dissolution. Very recently, we have demonstrated that the E/S ratio of Li-S cells has a significant effect on both performance and theoretical energy density of Li-S batteries. Since the lower-bound for E/S ratio is restricted by the solubility of LiPS in the organic electrolyte, the theoretical energy density of Li-S batteries is significantly reduced. Experimentally, it was approved that when the LiPS concentration reached to the solubility limitation in the electrolyte, the reaction rate of reducing sulfur to LiPS in the cathode will reduce significantly [4]. In this talk, we will discuss the relationship between theoretical specific energy and the solubility of LiPS in the electrolyte. The theoretical specific energy of a Li-S battery can be expressed as: e=CLVcell/(MC+MA+Mele) (1) where, CL is the lower capacity in amount of cathode and anode, Vcell is the cell voltage (e.g. 2.1 V), MC, MA, Mele are weights of sulfur (cathode), lithium (anode), and electrolyte, respectively. In an ideal case, capacities of cathode and anode are equal and to be MA=2×6.94MC/32.065, the atomic weights of lithium and sulfur are 6.94 and 32.065 g/mol, respectively, the capacity is CL=cSMC where cS=1,672 mAh/g is the theoretical specific capacity of sulfur. The minimum weight ratio of electrolyte to sulfur is: Mele/MC=rele/32.065S (2) where, rele is the mass density of electrolyte (e.g. 1.2 g/cm3) and S is the solubility of LiPS in unit of M[S]/L; therefore, the theoretical specific energy for a Li-S battery is: e=3511/(1.4327+37.42/S[M/L])[Wh/kg] (3) Fig. 1 shows the theoretical specific energy of Li-S batteries when the LiPS solubility is considered as an intrinsic limitation for Li-S battery capacity. Here only the weight of active electrode material, such as sulfur and lithium, as well as electrolyte weight is included in calculation. From Fig. 1, it can be seen that for commonly used electrolytes with LiPS solubility less than 8 M[S]/L, the theoretical energy is less than 575 Wh/g. Fig. 2 further presents a series of specific energy calculation for Li-S battery with different E/S ratios. From Fig. 2(a), it can be seen that the electrolyte weight would dominate in a Li-S battery even in relatively low E/S conditions. Fig. 2(b) plots the effective theoretical specific capacity of a Li-S battery. Fig. 2(c) that the reduced effective specific capacity introduced by LiPS solubility limit would offset electrolyte weight loss under low E/S conditions, making the theoretical specific energy curve relatively flat under low E/S region, while without considering LiPS solubility the specific energy will increase sharply when E/S ratio is decreased. The above results imply that reducing E/S ratio would become pointless when LiPS solubility is reached. For further boosting capacity of Li-S batteries, electrolyte with even higher LiPS solubility is favorable. Fig. 2(d) plots the specific energy of an ideal Li-S cell under different LiPS solubility. Reference: [1] A. Manthiram, Y. Fu, S. Chung, C. Zu, Y. Su, Rechargeable Lithium–Sulfur Batteries, Chem. Rev. 114 (2014) 11751–11787. [2] Z.W. Seh, Y. Sun, Q. Zhang, Y. Cui, Designing high-energy lithium–sulfur batteries, Chem. Soc. Rev. (2016). [3] W. Kang, N. Deng, J. Ju, Q. Li, D. Wu, X. Ma, et al., A review of recent developments in rechargeable lithium-sulfur batteries, Nanoscale. 1 (2016) 16541–16588. [4] C. Shen, J. Xie, M. Zhang, J.P. Zheng, M. Hendrickson, and E.J. Plichta, J. Electrochem. Soc., 164 (2017) A1220-A1222. Figure 1

Lithium-sulfur (Li-S) batteries are regarded as one of the most promising next-generation energy storage technologies due to their high theoretical specific capacity, material abundance, and low production costs. Despite these advantages, the commercialization of Li-S batteries remains limited, primarily due to significant technical challenges,1-3 including the dissolution and shuttling of lithium polysulfides (PS), a major cause of fast capacity degradation over cycling in Li-S batteries. In our recent work,4 we introduced a novel sulfur cathode design comprising a thin film of nanolayer-polymer-coated carbons (NPC) deposited on sulfur electrodes (NPC-S). This advanced architecture enabled Li-S battery cells to achieve a high specific capacity of ~1,600 mAh/g, approaching sulfur's theoretical specific capacity, without introducing appreciable dead weight or volume to the battery.In this talk, we will present our continued efforts to further develop the advanced Li-S battery technology with the novel strategy of combining the NPC-S approach with a cycle-stabilizing and safety-enhancing approach in the advanced Li-S batteries. This synergistic strategy resulted in not only the near-theoretical specific capacity of sulfur (Figure 1a), but also a significantly improved long-term cycle stability, ~90% capacity retention after cycling at 1C rate for 500 charge-discharge cycles (Figure 1b). We will present various analytical characterizations and theoretical calculations to elucidate the reaction mechanisms of the outstanding performance of the advanced Li-S battery technology. Acknowledgment This work was supported by the Linda and Larry Pearson Endowed Chair at the Leslie A. Rose Department of Mechanical Engineering, South Dakota School of Mines & Technology, and the South Dakota Governor Research Center for Electrochemical Energy Storage. References Wang, S.; Wang, Z.; Chen, F.; Peng, B.; Xu, J.; Li, J.; Lv, Y.; Kang, Q.; Xia, A.; Ma, L. "Electrocatalysts in lithium-sulfur batteries". Nano Research 2023, 1-30.Zhao, F. L.; Xue, J. H.; Shao, W.; Yu, H.; Huang, W.; Xiao, J. "Toward high-sulfur-content, high-performance lithium-sulfur batteries: Review of materials and technologies". J Energy Chem 2023, 80, 625-657. DOI: 10.1016/j.jechem.2023.02.009.Hu, X.; Huang, T.; Zhang, G.; Lin, S.; Chen, R.; Chung, L.-H.; He, J. "Metal-organic framework-based catalysts for lithium-sulfur batteries.". Coordination Chemistry Reviews 2023, 475, 214879.Hasan, M. W.; Huynh, K.; Lama, B.; Razzaq, A. A.; Smdani, M. G.; Akter, F. N.; Maddipudi, B.; Shende, R.; Paudel, T. R.; Xing, W. "A Highly Effective Polysulfide-Trapping Approach for the Development of High Energy Density, Scalable Lithium-Sulfur Batteries". J Electrochem Soc 2024. DOI: 10.1149/1945-7111/ad3ebf. Figure 1

As a result of the high theoretical energy density of lithium-sulfur (Li-S) batteries, they have been accepted as the next-generation energy storage system. Nevertheless, the current performance of Li-S batteries is still unsatisfactory under lean electrolyte conditions. It is because of sluggish deposition of Li2S2/Li2S passivating the sulfur/electrolyte interface, thus leading to lower sulfur use and bad rate performances of Li-S batteries. Herein, a novel Co9S8 nanorod-based catalytic interlayer placed between the cathode and separator is proposed. The interlayer possesses a three-dimensional open structure, which facilitates electrolyte infiltration but without trapping too much electrolyte. As a result, the electrocatalytic Co9S8 nanorods within the interlayer promote faster electrochemical kinetics and enhance the conversion of polysulfides, thus resulting in a higher specific discharge capacity and better rate and cycling performance. This work proves a feasible method in developing practical Li-S batteries.

Lithium Sulfur battery is supposed to be one of the most promising candidates in next generation rechargeable batteries. Owing to the high theoretical specific capacity (~1675 mAh/g) and abundance of sulfur, lithium-sulfur battery can achieve high energy density with relatively low cost. However, the practical energy density is much smaller than the theoretical value. The operation of Li-S batteries under lean electrolyte condition was revealed by investigating Li-S pouch cell under different electrolyte/sulfur ratio. The cathode interfacial resistance was figured out in testing Electrochemical Impedance Spectroscopy (EIS) during discharging for different E/S ratio. The electrolyte resistance, interfacial resistance as well as the charge transfer resistance were keeping changing in same trend for different E/S ratio. The changing was observed in both DOL/DME and DMSO electrolytes for all E/S ratios we tested. Such resistance behaviors were also confirmed by enforced Galvanostatic Intermittent Titration Technique (GITT). By applying enforced GITT onto the lean electrolyte cell, it can even get as high specific capacity as flood electrolyte cells did. We propose that the cathode interfacial resistance can be one of the reasons which is challenging the Li-S battery to achieve its theoretical specific capacity under lean electrolyte condition. Such mechanistic understanding of the Li-S battery under lean electrolyte condition can provide guidance in developing high energy density Li-S battery.

Introduction As the demand for energy is harshly increasing nowadays, great effort has been devoted to developing various advanced energy-storage technologies with high energy density, long-term cyclability, and inexpensive costs. The lithium-ion battery technology has been the mainstream option for the portable energy supply for the past decades. However, the commercial lithium-ion battery has limited cathode capacity and energy density of about 170 mAh g-1 and 600 Wh kg-1, as well as the high costs of $10,000 per ton. To further increase the cathode capacity and lower the fabrication costs, sulfur, with a high theoretical capacity of 1,675 mAh g-1, a high theoretical energy density of 2,600 Wh kg-1 in lithium-sulfur batteries, and a cheap price of $150 per ton, has been chosen to become new cathode materials. Thus, lithium–sulfur battery, as an alternative branch of lithium-ion batteries, is a potential technology to solve the problems in portable energy supply.In lithium–sulfur system, multiple redox reactions occur during different steps of charge and discharge reactions. In the discharge process, the solid-state sulfur (S8) will be reduced to form liquid-state lithium polysulfides (Li2Sx, 4 ≤ x ≤ 8) and solid-state lithium sulfides (Li2S2/Li2S). The lithium sulfides will be charged back to solid-state sulfur. These reactions in charge and discharge processes repeat during cycling. Three key factors, the sulfur loading, the sulfur content, and the electrolyte-to-sulfur ratio, have been thoroughly researched for developing high-performance lithium–sulfur batteries in the past two decades. To commercialize the lithium–sulfur battery technology, limits on these three factors have been set, which are a sulfur loading of 5 mg cm-2 and above, a sulfur content of 65 wt% and above, and an electrolyte-to-sulfur ratio of 10 μL mg-1 and below. However, due to the complex reaction steps in lithium–sulfur system, these three factors are conflicted or cannot be achieved simultaneously in most of the research cases. Results and Discussion Here, in our presentation, we report a high-loading polysulfide cathode, achieving both high sulfur content and low electrolyte-to-sulfur ratio at the same time. A non-nanoporous carbon nanotube/nanofiber (CNT/CNF) is adopted as the electrode substrate to accommodate the active material, liquid polysulfide catholyte, forming a polysulfide cathode with a high sulfur loading of 8.64 mg cm-2, a high sulfur content of 68 wt%, and low electrolyte-to-sulfur ratios of 4–7 μL mg-1. With such a cathode design, the lithium-sulfur cell attain high discharge capacities of 630–870 mAh g-1 and 580–631 mAh g-1 at C/10 and C/5 cycling rates, which corresponds to the high energy densities of 10.5–11.5 and 11.4–15.7 mWh cm-2. In addition to the high electrochemical utilization, our lean-electrolyte lithium-sulfur cells demonstrate a long-term cyclability of 200 cycles.As a result, we further investigate the possible failure mechanism for a high-loading polysulfide cathode operating in a lean-electrolyte cell under a semi-dry electrolyte condition. The extended cycling test is performed to explore the discharge and charge efficiency as well as the lithiation and delithiation mechanisms. Two cycling rates, C/10 and C/5, are applied for comparison. It reveals that due to the semi-dry electrolyte condition, the decomposition of the polysulfide catholyte occurs during extended cycles. The overcharge issue is thus occurred as a result of the rapid consumption of electrolyte, and leads to slow ion diffusion, decreased Coulombic efficiency, and irreversible capacity loss. Additionally, the decayed cycling performances are more easily observed at the slow C/10 cycling rate than at the fast C/5 cycling rate. Conclusion In summary, according to the excellent cycling performances of our cell design with a high-loading cathode, high sulfur content, and lean electrolyte addition, we might be very close to overcome the three limiting factors for commercialization of lithium–sulfur battery technology. Moreover, the failure analysis of our lean-electrolyte lithium-sulfur cell demonstrates the main challenges in developing a lean-electrolyte lithium–sulfur cell. The attainment of a high and stable Coulombic efficiency as well as the fast electrolyte consumption during regular cycling rate would challenge the development of lean-electrolyte lithium-sulfur cell with more practical cell design parameters.

Lithium-sulfur (Li-S) batteries are considered as one of the most potential next-generation rechargeable batteries due to their high theoretical energy density. However, some critical issues, such as low capacity, poor cycling stability, and safety concerns, must be solved before Li-S batteries can be used practically. During the past decade, tremendous efforts have been devoted to the design and synthesis of electrode materials. Benefiting from their tunable structural parameters, hollow porous carbon materials (HPCM) remarkably enhance the performances of both sulfur cathodes and lithium anodes, promoting the development of high-performance Li-S batteries. Here, together with the templated synthesis of HPCM, recent progresses of Li-S batteries based on HPCM are reviewed. Several important issues in Li-S batteries, including sulfur loading, polysulfide entrapping, and Li metal protection, are discussed, followed by a summary on recent research on HPCM-based sulfur cathodes, modified separators, and lithium anodes. After the discussion on emerging technical obstacles toward high-energy Li-S batteries, prospects for the future directions of HPCM research in the field of Li-S batteries are also proposed.

Lithium sulfur (Li-S) battery is a promising alternative technology of lithium ion batteries. However, due to the complicity of the chemistry in Li-S batteries, the mechanism is not well understood. In addition, the co-existence of soluble species and insoluble species limits the application of other characterization techniques. The sensitivity and element selectivity make NMR spectroscopy a powerful tool to study the changes in local chemical environment and speciation process in Li-S batteries. In this study, in situ 7Li NMR spectroscopy was employed where plastic pouch cells were assembled and cycled in the magnet while NMR spectra were acquired simultaneously. Method to quantitatively study entire lithium inventory in a Li-S battery is developed and implemented, and the cell design is optimized for electrochemical performance and spectroscopic resolution. This methodology can be readily extended to Li-S batteries with other electrolytes where the speciation process can be tracked and analyzed. The development of electrolyte will also benefit greatly from the detailed understanding of the Li-S battery speciation process as well as the additive development. [1] See, et. al., J. Am. Chem. Soc., 2014, 136 (46), pp 16368–16377 [2] Xiao, et. al., Nano Lett., 2015, 15, 3309-3316

Lithium-sulfur (Li-S) batteries have been intensively investigated as a next-generation rechargeable battery due to their high energy density of 2600 W·h kg(-1) and low cost. However, the systemic issues of Li-S batteries, such as the polysulfide shuttling effect and low Coulombic efficiency, hinder the practical use in commercial rechargeable batteries. The introduction of a conductive interlayer between the sulfur cathode and separator is a promising approach that has shown the dramatic improvements in Li-S batteries. The previous interlayer work mainly focused on the physical confinement of polysulfides within the cathode part, without considering the further entrapment of the dissolved polysulfides. Here, we designed an ultrathin poly(acrylic acid) coated single-walled carbon nanotube (PAA-SWNT) film as a synergic functional interlayer to address the issues mentioned above. The designed interlayer not only lowers the charge transfer resistance by the support of the upper current collector but also localizes the dissolved polysulfides within the cathode part by the aid of a physical blocking and chemical bonding. With the synergic combination of PAA and SWNT, the sulfur cathode with a PAA-SWNT interlayer maintained higher capacity retention over 200 cycles and achieved better rate retention than the sulfur cathode with a SWNT interlayer. The proposed approach of combining a functional polymer and conductive support material can provide an optimiztic strategy to overcome the fundamental challenges underlying in Li-S batteries.

High Coulombic efficiency cathode with nitryl grafted sulfur for Li-S battery

Developing lithium-sulfur cells with a high-loading cathode at a lean-electrolyte condition is the key to bringing the lithium-sulfur technology into the energy-storage market. However, it has proven to be extremely challenging to develop a cell that simultaneously satisfies the abovementioned metrics while also displaying high electrochemical efficiency and stability. Here, we present a concept of constructing a conductive cathode substrate with a low surface area and optimized nanoporosity (i.e., limited micropores in the porous matrix) that enables achieving a high sulfur loading of 13 mg cm-2 and a high sulfur content of 75 wt % with an extremely low electrolyte/sulfur ratio of just 4.0 μL mg-1. The high-loading nanocomposite cathodes demonstrate high-areal capacities of 9.3 mA h cm-2, high energy densities of 18.6 mW h cm-2, and superior cyclability with excellent capacity retention of 85% after 200 cycles. These values are higher than the benchmarks set up for developing future commercial lithium-sulfur cells (i.e., areal capacity of >2-4 mA h cm-2, energy density of >8-13 mW h cm-2, and a long cycle life of 200 cycles with a capacity retention of 80%). The cathode design further exhibits high-rate capability from C/20 to 1 C rates and great potential to attain ultrahigh sulfur loading and a content of 17 mg cm-2 and 80 wt %. The key nanostructural feature that enables realizing fast-charge transport is the low surface area and limited microporosity that avoid the fast consumption of the electrolyte during cell cycling.

Lithium-sulfur batteries are among the most promising low-cost, high-energy-density storage devices. However, the inability to host a sufficient amount of sulfur in the cathode while maintaining good electrochemical stability under a lean electrolyte condition has limited the progress. The main cause of these challenges is the sensitivity of the sulfur cathode to the cell-design parameters (i.e., the amount of sulfur and electrolyte) and the experimental testing conditions (i.e., cycling rates and analysis duration). Here, a hot-pressing method is presented that effectively encapsulates a high amount of sulfur in the cathode within only 5 s, resulting in high sulfur loading and content of, respectively, 10 mg cm-2 and 65 wt%. The hot-pressed sulfur (HPS) cathodes exhibit superior dynamic and static electrochemical performance under a broad cycling-rate (C/20-1C rates) and low electrolyte/sulfur ratio (6 µL mg-1 ) conditions. The dynamic cell stability is demonstrated by high gravimetric and areal capacities of, respectively, 415-730 mAh g-1 and 7-12 mAh cm-2 at C/20-1C rates with a high capacity retention of over 70% after 200 cycles. The static cell stability is demonstrated by excellent shelf life with low self-discharge and stable cycle life on storing for over one year.