Solid-state Lithium-sulfur Batteries Research Articles

Enhanced performance of graphene-incorporated electrodes for solid-state lithium-sulfur batteries through facilitated ionic diffusion pathways

Significant progress has been achieved in advancing all-solid-state lithium-sulfur batteries through the development of sulfide solid electrolytes. Nonetheless, a challenge lies in creating a percolated ion–electron conduction path with intimate contact between charge carriers throughout the cathode which is crucial for enhancing overall efficiency and addressing issues related to slow kinetics and impedance during battery operation. This study introduces a framework elucidating how the integration of graphene enhances electrode performance by refining ionic diffusion pathways. An idealized ionic diffusion pathway characterized by a continuous ionic network, facilitating minimum diffusion distances, is proposed. Through a parametric study substituting portions of ionic and electronic conductive agents with graphene, the impact on total ionic and electronic conductivity of positive electrodes was comprehended. The findings underscore the critical role of optimum graphene content, which fills the gaps between ionic conductive materials and creates the shortest diffusion paths for ions and electrons. While incorporating graphene into cathode electrodes is not novel, it is noteworthy that graphene, as a mixed ion–electron conductive material, significantly enhances ion mobility due to its 2D structure, addressing a crucial aspect of cathode performance. Upon achieving optimum composite formulation, empirical findings demonstrate substantial performance improvement, including a 17.7% increase in initial capacity and a remarkable 21% enhancement in capacity retention compared to electrodes without graphene.

Modulating Ionic Conduction and Accelerating Sulfur Conversion Kinetics through Oxygen Vacancy Engineering for High‐Performance Solid‐State Lithium‐Sulfur Batteries

AbstractPoly(ethylene oxide) (PEO)‐based solid‐state lithium‐sulfur batteries (SSLSBs) have garnered considerable attention as potential energy storage solutions owing to their exceptional specific energy, ease of processing, and economic viability. Nevertheless, the inherently low Li+ conductivity of the PEO electrolyte and the inevitable dissolution of lithium polysulfides (LiPSs) within the sulfur cathode hinder the solid‐state sulfur conversion kinetics and lead to significant loss of active materials, thus posing challenges for practical applications. Herein, these concerns are addressed by incorporating oxygen vacancy enriched‐Nb22W20O102‐x (NWOx) nanorods as cathode additives in high‐performance PEO‐based SSLSBs. The uniformly dispersed NWOx nanorods effectively modify the coordination environment of Li ions by increasing the concentration of free Li ions in the PEO catholyte and alleviating the shuttle effect of dissolved LiPSs. Consequently, the developed SSLSB demonstrates excellent cyclic stability and rate capability. Specifically, it achieves a high discharge capacity of 1208.6 mAh g−1 during the initial cycle and maintains 927.8 mAh g−1 after 200 cycles at 0.1 C. Moreover, such a configuration can accommodate a high loading of active materials with stable capacity retention. Overall, this study presents an effective approach for developing solid‐state sulfur cathodes in PEO‐based SSLSBs.

The role of nanoporous carbon materials for thiophosphate-based all solid state lithium sulfur battery performance

Due to their high theoretical energy density, all solid state lithium sulfur batteries (LS-SSB) represent one of the most promising candidates for next-generation energy storage systems. Whilst high sulfur utilizations have been published for several cathode compositions and preparation methods in recent years, there is still a lack of clarity regarding the influence of the used carbon. Furthermore, LS-SSBs face challenges in up-scaling as the common preparation methods including high energy ball milling are time consuming, batch-wise and need high energy impact. In this study, high sulfur utilization >1600 mAh gS−1 and reversibility with 80 % of initial discharge capacity after 60 cycles is achieved, using a more time-efficient preparation method with drastically lowered energy impact by selecting a suitable carbon. Additionally, the influence of the carbon nanostructure on the electrochemical performance is discussed. This study provides guidance in selecting nanostructured carbon materials to enable cost-efficient, up-scalable preparation methods for LS-SSBs without compromising on the excellent electrochemical performance.

Selenium-Doped Sulfurized Polyacrylonitrile Hybrid Cathodes with Ultrahigh Sulfur Content for High-Performance Solid-State Lithium Sulfur Batteries.

The solid-state lithium sulfur battery (SSLSB) is an attractive next-generation energy storage system by reason of its remarkably high energy density and safety. However, the SSLSB still faces critical challenges, such as sluggish reaction kinetics, mismatched interface, and undesirable reversible capacity. Herein, a high-performance SSLSB is reported using sulfurized polyacrylonitrile with rich selenium-doped sulfur (Se/S-S@pPAN) as a cathode and poly(ethylene oxide)/Li7La3Zr1.4Ta0.6O12 (PEO-LLZTO) as an electrolyte. The sulfur content of the cathode up to 60.9 wt % can be achieved by dispersing selenium sulfide (SeSx) species in the sulfurized polyacrylonitrile (S@pPAN) skeleton at a molecular level. Selenium as a eutectic accelerator can be uniformly distributed in the composite through the Se-S bond and can accelerate the reaction kinetics. The PEO-LLZTO hybrid solid-state electrolyte (SSE) displays an attractive electrochemical performance and provides an intimate contact with electrodes. At 60 °C, Se/S-S@pPAN delivers an impressive discharge capacity of 1042 mAh g-1 at 0.1C and 445 mAh g-1 at 1C. Additionally, the LiFePO4 cathodes combined with PEO-LLZTO deliver a high reversible capacity (158.9 mAh g-1, 1C) and an ultralong lifespan (a capacity retention of 80%, 1000 cycles) at 1C. The synergetic design of the high-performance sulfur cathode and the organic/inorganic hybrid electrolyte is crucial for enabling the high-performance SSLSB.

Laminar Composite Electrolytes with Nanoporous Sulfonated Covalent Organic Framework-Confined Crown Ether for Solid-State Lithium–Sulfur Batteries

Laminar Composite Electrolytes with Nanoporous Sulfonated Covalent Organic Framework-Confined Crown Ether for Solid-State Lithium–Sulfur Batteries

Interfacial self-healing polymer electrolytes for long-cycle solid-state lithium-sulfur batteries

Coupling high-capacity cathode and Li-anode with solid-state electrolyte has been demonstrated as an effective strategy for increasing the energy densities and safety of rechargeable batteries. However, the limited ion conductivity, the large interfacial resistance, and unconstrained Li-dendrite growth hinder the application of solid-state Li-metal batteries. Here, a poly(ether-urethane)-based solid-state polymer electrolyte with self-healing capability is designed to reduce the interfacial resistance and provides a high-performance solid-state Li-metal battery. With its dynamic covalent disulfide bonds and hydrogen bonds, the proposed solid-state polymer electrolyte exhibits excellent interfacial self-healing ability and maintains good interfacial contact. Full cells are assembled with the two integrated electrodes/electrolytes. As a result, the Li||Li symmetric cells exhibit stable long-term cycling for more than 6000 h, and the solid-state Li-S battery shows a prolonged cycling life of 700 cycles at 0.3 C. The use of ultrasound imaging technology shows that the interfacial contact of the integrated structure is much better than those of traditional laminated structure. This work provides an interesting interfacial dual-integrated strategy for designing high-performance solid-state Li-metal batteries.

Novel PEO-based composite solid electrolytes for All-Solid-State Li-S battery

Solid polymer electrolytes (SPEs) were investigated for several decades due to their good compatibility with electrodes. However, meeting the essential requirements for solid polymer electrolytes, including enhanced ionic conductivity, superior solubility with conductive lithium salts, and robust interface stability when in contact with a Li anode, remains a formidable challenge. In our work, we found that transition metal carbides (NiNbCeC) over mesoporous silica (SBA-15) can be filled into the Polyethylene Oxide (PEO) matrix to form composite solid electrolytes which can greatly improve the ionic conductivity of PEO. We investigate a series of transition metal carbides with varying mass ratios of Cerium (5%, 10%, and 20%) to fabricate All-Solid-State Li-S batteries (ASSLi-S). Our results demonstrate that different mass ratios of Cerium play a pivotal role in enhancing the ionic conductivity of the composite solid electrolytes, reducing impedance levels from 9150 O (20% Ce) to 4000 O (5% Ce) to 1730 O (10% Ce). At room temperature, the high initial specific capacity at 1C and reversible specific capacity after 100 cycles are 525 and 363 mAh/g, 605 and 403 mAh/g, 246.3 mAh/g and 63.28 mAh/g for 5% Ce, 10%, and 20%, respectively. Furthermore, long-term cycling tests of ASSLi-S cells at 0.5C reveal promising performance, with the cell containing 10% Ce solid electrolytes delivering an initial specific capacity of 1165.7 mAh/g and maintaining 335 mAh/g after 200 cycles. This represents a significant breakthrough, demonstrating that PEO-based solid electrolytes can achieve impressive electrochemical results at room temperature. SEM characterization was employed to assess the volume change in the solid electrolyte layer and elemental distribution of solid electrolyte materials through cross-sectional analysis. This analysis revealed that the failure modes of solid-state Li-S cells can also be attributed to the migration of sulfur elements from the cathode to the solid electrolyte layer during the cycling process. XRD was utilized to study the crystallinity of composite solid electrolytes. This study represents a significant stride in the progress of high-performance solid polymer electrolytes for All-Solid-State Li-S batteries, shedding light on the failure modes of such batteries. It underscores the potential of composites based on transition metal carbides in addressing crucial challenges for their practical implementation in Solid-State Lithium-Sulfur Batteries.

A Fully Amorphous, Dynamic Cross-Linked Polymer Electrolyte for Lithium-Sulfur Batteries Operating at Subzero-Temperatures.

Solid-state lithium-sulfur batteries have shown prospects as safe, high-energy electrochemical storage technology for powering regional electrified transportation. Owing to limited ion mobility in crystalline polymer electrolytes, the battery is incapable of operating at subzero temperature. Addition of liquid plasticizer into the polymer electrolyte improves the Li-ion conductivity yet sacrifices the mechanical strength and interfacial stability with both electrodes. In this work, we showed that by introducing a spherical hyperbranched solid polymer plasticizer into a Li+ -conductive linear polymer matrix, an integrated dynamic cross-linked polymer network was built to maintain fully amorphous in a wide temperature range down to subzero. A quasi-solid polymer electrolyte with a solid mass content >90 % was prepared from the cross-linked polymer network, and demonstrated fast Li+ conduction at a low temperature, high mechanical strength, and stable interfacial chemistry. As a result, solid-state lithium-sulfur batteries employing the new electrolyte delivered high reversible capacity and long cycle life at 25 °C, 0 °C and -10 °C to serve energy storage at complex environmental conditions.

G-C3N4 Boosting the Interfacial Compatibility of Solid-State Lithium-Sulfur Battery

The poor interfacial compatibility between solid electrolyte and lithium metal anode is one of the main obstacles to the development of solid lithium metal battery. Herein, the poly (1,3-dioxolane) (PDOL) polymer is combined with g-C3N4 powders to form a flexible and dense composite solid electrolyte film, which not only possesses high ionic conductivity of 3.7 × 10−4 S·cm−1, high ion migration number up to 0.86, and wide electrochemical stability window of 5.0 V, but also is helpful for inhibiting the growth of lithium dendrites to improve the interfacial stability of the lithium anode and close contact with cathode. The prepared S/g-C3N4-PDOL/Li battery exhibits good rate and cycle performances with a capacity of 550 mAh g−1 at 1 C, and 1150 mAh g−1 at 0.1 C with a capacity retention rate of 83% after 100 cycles. The dense Li3N layer generated by the reaction between g-C3N4 and Li gives g-C3N4/PDOL composite electrolyte a high inhibition ability of lithium dendrites. This composite solid electrolyte film with an interface modification function has good practical application prospects in lithium-sulfur batteries.

A high ion conductive solid electrolyte film and interface stabilization strategy for solid-state Li-S battery

Lithium-sulfur (Li-S) batteries are regarded as a potential next-generation electrochemical energy storage technology. However, polysulfide shuttle effect and lithium dendrite growth always worsen the battery's cycling performance, especially, the safety problem of liquid electrolyte has also become a major challenge to the development and application of Li-S batteries. Herein, a high ion conductive poly(1,3-dioxolane) solid electrolyte film (PDOL) was introduced in Li-S battery, which hinders the shuttle of polysulfides, and forms a uniform LiF protective layer on the lithium metal contact surface to inhibit the growth of lithium dendrites. Meanwhile, the problem of high interfacial impedance in solid-state Li-S batteries was also solved by adding a trace amount of flexible organic ether electrolyte to the solid electrolyte/electrode interface. The assembled quasi-solid-state S/PDOL/Li cell shows low interfacial impedance less than 75 Ω and can be stably cycled over 500 times at 0.1 C. This rigid-flexible solid electrolyte design method provides a practical idea for the development of high-performance solid-state Li-S batteries.

High energy and sustainable solid-state lithium-sulfur battery enabled by the force-bearing cathode and multifunctional double-layer hybrid solid electrolyte

High energy and sustainable solid-state lithium-sulfur battery enabled by the force-bearing cathode and multifunctional double-layer hybrid solid electrolyte

Optimizing Sulfur Utilization in High Loading Cathode for All-Solid-State Lithium-Sulfur Battery

All Solid-state Lithium-Sulfur battery (ASSLSB) possesses a great promise in providing a safe, high energy density, and low cost battery technology for vehicle electrification and grid energy storage. To achieve practically high specific energy in ASSLSB (e.g., >400 Wh/Kg), sulfur cathodes with high areal capacity (>6 mAh cm-2) are essentially needed to offset the relatively low working voltage of elemental sulfur cathode (1.9 V vs. Li). This requires high mass loading sulfur cathodes by maximizing both sulfur content in the whole electrode and sulfur utilization rate to reduce the parasitic weights. An optimal electrode architecture featuring sufficiently connected sulfur/solid electrolyte/carbon triple interfaces is desired to enable sulfur’s fast accessibility to electron and Li-ion simultaneously. Due to the non-flowability of those three solid components, however, it is very hard to maximize the contact of trip solid phases, which need new insights of the materials design and processing technology.This work looks at carbon microstructures and their impact on triple-point contact between electrochemically active sulfur, carbon, and the solid-state electrolyte (SSE) that comprises most composite cathodes in ASSLSB systems. While significant work has gone into understanding and developing novel carbon host structures for liquid Li-S cells for improving sulfur utilization, polysulfide trapping, better understanding is needed for ASSLSBs. Specifically, how sulfur infiltration, loading, and spatial distribution within the porous carbon host impacts sulfur utilization. Understanding how the infiltrated sulfur that resides in the porous carbon host connects with both carbon and solid electrolyte networks across the whole electrode structure and maintains its robustness during the repeated cell cycling is needed to achieve full utilization in high sulfur loading electrodes. The solid sulfur cathode system examined in the present study is a composite of porous carbon, sulfur, and a sulfide-based solid electrolyte. A combination of porous carbon hosts is investigated and correlated to the cell performance at practical conditions. Advanced characterization and computational tools are used to further elucidate the key parameters for high sulfur utilization in ASSLSBs with high sulfur loading cathodes. Details of the study will be presented and discussed at the meeting.Reference:(1) Nagata, H. and Y. Chikusa (2016). "All-Solid-State Lithium–Sulfur Battery with High Energy and Power Densities at the Cell Level." Energy Technology 4(4): 484-489(2) Banerjee, A., et al. (2020). "Interfaces and Interphases in All-Solid-State Batteries with Inorganic Solid Electrolytes." Chemical Reviews 120(14): 6878-6933.

Cathode Development for All Solid-State Lithium-Sulfur Batteries

With higher demand for alternative energy sources that are cleaner and more sustainable, research has shifted towards various lithium metal-based batteries with higher capacities than lithium-ion (LIBS). The study of lithium-sulfur energy storage systems has been heavily influenced due to the high gravimetric capacity of sulfur (1672 mA h g−1) and its abundance in the Earth’s crust. To increase the safety of lithium-sulfur batteries, solid state systems have been developed. These systems are also advantageous as the polysulfide shuttle effect normally seen in organic liquid electrolytes (OLEs) is eliminated, decreasing degradation due the irreversible reactions. Some of the most successful electrolytes found for lithium-sulfur all solid-state batteries (ASSLSBs) are ceramic based electrolytes. These electrolytes have high ionic conductivities (ranging 10-3-10-4 S cm-1) and do not pose any safety risks. However, one of the biggest bottlenecks of ASSLSBs is the utilization and accessibility of sulfur during cycling.To ensure these attributes are met, carbon materials have been used as supports; additionally, carbon also aids in electron transport due sulfur’s low electrical conductivity (10 -15 S m-1).Sulfur is typically dispersed or deposited on these carbon supports in different approaches before a full cathode composition is developed. Varying synthesis methods of sulfur deposition onto reduced graphene oxide are studied to determine which synthesis method provides the most accessibility for sulfur utilization. Utilization and accessibility will be analyzed through cyclic voltammetry, galvanostatic charge and discharge and impedance measurements to obtain characteristic voltammograms, specific capacity curves and Nyquist plots. Cells are assembled in PEEK Split cells using ceramic based electrolyte and lithium metal for the development of a noble ASSLSB.

Cross-Linked Solid Polymer-Based Catholyte for Solid-State Lithium-Sulfur Batteries

All-solid-state lithium-sulfur batteries (ASSLSBs) are a promising next-generation battery technology. They exhibit high energy density, while mitigating intrinsic problems such as polysulfide shuttling and lithium dendrite growth that are common to liquid electrolyte-based batteries. Among the various types of solid electrolytes, solid polymer electrolytes (SPE) are attractive due to their superior flexibility and high safety. In this work, cross-linkable polymers composed of pentaerythritol tetraacrylate (PETEA) and tri(ethylene glycol) divinyl ether (PEG), are incorporated into sulfur–carbon composite cathodes to serve a dual function as both a binder and electrolyte, as a so-called catholyte. The influence of key parameters, including the sulfur–carbon ratio, catholyte content, and ionic conductivity of the electrolyte within the cathode on the electrochemical performance, was investigated. Notably, the sulfur composite cathode containing 30 wt% of the PETEA-PEG copolymer catholyte achieved a high initial discharge capacity of 1236 mAh gS−1 at a C-rate of 0.1 and 80 °C.

Development of carbon materials for sulfur cathodes in inorganic-based solid-state lithium–sulfur batteries

Inorganic-based solid-state lithium–sulfur batteries (SSLSBs) with high energy density and high safety have attracted wide attention as they are one of the most promising energy storage devices to meet future market requirements. However, the development of SSLSBs faces various challenges due to the unreasonable structural design in sulfur cathodes. Carbon is one of the indispensable components in sulfur cathodes. The rational design of carbon materials becomes an important strategy to address the challenges in sulfur cathodes. This review summarizes recent literature about the design and application of carbon materials for sulfur cathodes in inorganic-based SSLSBs. It starts with the introduction of different carbon materials from zero-dimensional to three-dimensional carbon materials. Particularly, this review paper highlights the structural design of carbon materials and the cathode fabrication methods, toward improving the conductivity of cathodes, buffering volume changes in cathodes, reducing interfacial resistance among cathode components, and increasing the mass loading of active materials. Finally, the existing challenges and promising solutions for carbon materials in the cathodes are discussed and proposed.

Uncoordinated chemistry enables highly conductive and stable electrolyte/filler interfaces for solid-state lithium–sulfur batteries

Composite-polymer-electrolytes (CPEs) embedded with advanced filler materials offer great promise for fast and preferential Li+ conduction. The filler surface chemistry determines the interaction with electrolyte molecules and thus critically regulates the Li+ behaviors at the interfaces. Herein, we probe into the role of electrolyte/filler interfaces (EFI) in CPEs and promote Li+ conduction by introducing an unsaturated coordination Prussian blue analog (UCPBA) filler. Combining scanning transmission X-ray microscope stack imaging studies and first-principle calculations, fast Li+ conduction is revealed only achievable at a chemically stable EFI, which can be established by the unsaturated Co-O coordination in UCPBA to circumvent the side reactions. Moreover, the as-exposed Lewis-acid metal centers in UCPBA efficiently attract the Lewis-base anions of Li salts, which facilitates the Li+ disassociation and enhances its transference number (tLi+). Attributed to these superiorities, the obtained CPEs realize high room-temperature ionic conductivity up to 0.36 mS cm-1 and tLi+ of 0.6, enabling an excellent cyclability of lithium metal electrodes over 4,000 h as well as remarkable capacity retention of 97.6% over 180 cycles at 0.5 C for solid-state lithium-sulfur batteries. This work highlights the crucial role of EFI chemistry in developing highly conductive CPEs and high-performance solid-state batteries.

Solid-State Electrolytes in Lithium-Sulfur Batteries: Latest Progresses and Prospects.

Solid-state lithium-sulfur batteries (SSLSBs) have attracted tremendous research interest due to their large theoretical energy density and high safety, which are highly important indicators for the development of next-generation energy storage devices. Particularly, safety and "shuttle effect" issues originating from volatile and flammable liquid organic electrolytes can be fully mitigated by switching to a solid-state configuration. However, their road to thecommercial application is still plagued with numerous challenges, most notably the intrinsic electrochemical instability of solid-state electrolytes (SSEs) materials and their interfacial compatibility with electrodes and electrolytes. In this review, a critical discussion on the key issues and problems of different types of SSEs as well as the corresponding optimization strategies are first highlighted. Then, the state-of-the-art preparation methods and properties of different kinds of SSE materials, and their manufacture, characterization and performance in SSLSBs are summarized in detail. Finally, a scientific outlook for the future development of SSEs and the avenue to commercial application of SSLSBs is also proposed.

Flexible solid-state lithium-sulfur batteries based on structural designs

Flexible solid-state lithium-sulfur batteries based on structural designs

Optimization on transport of charge carriers in cathode of sulfide electrolyte-based solid-state lithium-sulfur batteries

Optimization on transport of charge carriers in cathode of sulfide electrolyte-based solid-state lithium-sulfur batteries

Functional CNTs@EMIM+ -Br- Electrode Enabling Polysulfides Confining and Deposition Regulating for Solid-State Li-Sulfur Battery.

With an extremely high theoretical energy density, poly(ethylene oxide) (PEO)-based solid-state lithium-sulfur (Li-S) batteries are emerging as one of the most feasible and safest battery storage systems. However, the long-term cycling performance is severely impeded by polysulfides (Li2 Sn , n=4-8) shuttling and terrible electrode passivation from the electronic insulating Li2 S. Here, a novel cathode through chemically grafted 1-Ethyl-3-methylimidazolium bromide (EMIM+ -Br- ) to carbon nanotube (CNTs) for PEO-based Li-S batteries is reported (CNTs@EMIM-Br/S). Concretely, bi-functional mediator EMIM+ -Br- not only inhibits the polysulfides shuttling by strong chemical interactions via EMIM+ , but also facilitates the electrochemical kinetics for promoting the formation of 3D particulate Li2 S through high donor anion (Br- ). Satisfactorily, dual-function CNTs@EMIM-Br/S cathode exhibits high sulfur utilization with the capacity of up to 1298mAhg-1 , and keeps high capacity retention of 80.2% at 0.2C after 350 cycles, exceeding that of many reported PEO-based solid-state Li-S batteries. This work will open a new door for rationally designed architecture to enable the practical applications of advanced Li-S batteries.