Application Of Lithium-sulfur Batteries Research Articles

Sulfonate-rich polymer intercalated LDH artificial SEI film to enable high-stability Li-S batteries

Constructing a functional solid electrolyte interface (SEI) is of great significance to promote the practical application of lithium-sulfur batteries (LSBs). In this work, we design and synthesize a sulfonate-rich polymer intercalated LDH (LDH@PSS) and obtain organic-inorganic hybrid artificial SEI film on the surface of Li by spin-coating. The PSS intercalated LDH has a large layer spacing, which effectively improves the transfer kinetics of lithium ion. More importantly, the PSS polymer chain with rich sulfonic groups have strong electronegativity and can electrostatically repel polysulfide anions, which effectively suppress the self-discharge behavior caused by the “shuttle effect”. The symmetrical battery using LDH@PSS-Li shows a cycle life of up to 3100 h at 1 mA cm−2current density. In-situ optical tests also further confirm that the modified materials have excellent dendrite inhibition ability. The shuttle current and self-discharge tests show that LDH@PSS-Li can effectively prevent the parasitic reaction between polysulfide and lithium. After 200 cycles at 0.2 C, the battery maintains a reversible capacity of 1032.6 mAh cm−2, with a reduced capacity decay rate from 0.321 % of unprotected Li anode to 0.086 % per cycle. Consequently, LDH@PSS composite material as artificial SEI film has great application potential for the anodic protection of LSBs.

Hollow Structure Co1-xS/3D-Ti3C2Tx MXene Composite for Separator Modification of Lithium-Sulfur Batteries.

The commercial application of lithium-sulfur (Li-S) batteries has faced obstacles, including challenges related to low sulfur utilization, structural degradation resulting from electrode volume expansion, and migration of polysulfide lithium (LiPSs). Herein, Co1-xS/3D-Ti3C2Tx composites with three-dimensional (3D) multilayered structures are used as separator modification materials for Li-S batteries to solve these problems. The multilevel layered structure of Co1-xS/3D-Ti3C2Tx establishes an efficient electron and Li+ transfer path, alleviates the volume change during the battery charge-discharge process, and enhances the stability of the structure. In addition, the battery assembled with the modified separator shows excellent discharge capacity and cycle stability at 0.5 C and could maintain a high discharge capacity after 500 cycles. This work provides a method for designing highly dispersed metal sulfide nanoparticles on MXenes and extends the application of MXenes-based composites in electrochemical energy storage.

Fe3O4/FeP hetero-hybrids confer polypropylene separator robust inhibitory effect to the shuttle of soluble lithium polysulfides

High energy density (2600 Wh kg−1) and low price of sulfur make lithium-sulfur batteries (LSBs) become one of the most promising cost-effective energy storage systems in the future. However, lithium-sulfur batteries are still subject to the shuttle effect of soluble lithium polysulfides (LPSs). Herein, ferroferric oxide/iron phosphide (Fe3O4/FeP) hetero-hybrids have been developed and applied as a functional layer to modify the polypropylene separator to inhibit the shuttle of soluble LPSs. Meanwhile, Fe3O4/FeP layer can also accelerate the conversion of adsorbed soluble LPSs due to excellent catalytic performance. As a result, LSBs using Fe3O4/FeP-modified PP separators exhibit superior cycling stability and rate performance. At 0.1C and 5C, it can deliver 1399.8 and 382.1 mAh g − 1, respectively. At 2C, its average capacity decay rate is only 0.0093 % during the initial 900 cycles. Together with the desirable mechanical properties, the Fe3O4/FeP-modified PP separator demonstrate a great potential for practical application in LSBs.

Nitrogen and oxygen co-doped porous biocarbon@sulfur/carbon nanotubes as cathodes for high-performance lithium-sulfur batteries

Practical applications of lithium-sulfur batteries (LSBs) are limited due to the shuttle effect and the low conductivity of sulfur (S) and lithium polysulfide (LiPS). Currently, porous carbon materials doped with heteroatoms show extraordinary potential in this regard. Therefore, using KOH activation, we successfully prepared porous London Plane seed stems biochar (LPSC) with nitrogen and oxygen co-doping as the S carrier. We used carbon nanotubes (CNTs) as electrode coatings to improve the conductivity and suppress the shuttle effect. The results showed that the LPSC@S/CNTs composite electrode had an initial discharge capacity of 1090.4 mAh g−1 at 0.05 C. Furthermore, the capacity remained at 86.0 % after 300 cycles. This study provides a promising and sustainable approach to high-performance energy storage solutions.

Self-recovery catalysts of ZnIn2S4@In2O3 heterostructures with multiple catalytic centers for cascade catalysis in lithium−sulfur battery

The “shuttle effect” of soluble lithium polysulfides (LiPSs) in lithium-sulfur (Li-S) batteries can lead to sluggish kinetics of sulfur redox reactions and rapid capacity degradation, significantly limiting the practical application of Li-S batteries on a large scale. Herein, the cascade catalysis is achieved based on a self-recovery catalyst with multiple catalytic centers through a ZnIn2S4-In2O3-ZnIn2S4 sandwich-like structure to realize the tandem redox of S8 to Li2S. Specifically, the outer ZnIn2S4 nanosheet network can preferentially adsorb S8, and the middle In2O3 acts as an adsorption mediator to ensure the adsorption and conversion of S8 to long-chain Li2S6/Li2S4, and then the inner ZnIn2S4 can further catalyze the conversions from long-chain Li2S4 to short-chain Li2S2/Li2S. Reversibly, the ZnIn2S4 is better in decreasing the energy barrier of Li2S dissolution, and further converting it into elemental sulfur (S8). During this process, the In/O and In/Zn active sites are re-exposed by alternating catalytic mode to achieve the self-recovery of active site, thereby enhancing long-term catalytic activity. This work demonstrates that cascade catalysis can be achieved by self-recovery catalysts with multiple catalytic centers for LiPSs, providing novel insights into the design of multi-functional catalysts to rationally regulate LiPSs’ redox reactions

In situ self-assembled NiS2 nanoparticles on MXene nanosheets as multifunctional separators: Regulating shuttling effect and boosting redox reaction kinetics of lithium polysulfides

The notorious shuttling effect and sluggish redox kinetics towards lithium polysulfides (LiPSs) seriously hinder the practical application of lithium-sulfur (Li-S) batteries. The development of a multifunctional separator, as cooperator of trapper-catalyst-conductor, is deemed to be an efficient and feasible solving strategy. Herein, the NiS2/MXene nanocomposites with mesoporous structures were synthesized by the hydrothermal reaction, in which 0D ultrafine NiS2 nanoparticles were in situ self-assembled on 2D conductive MXene nanosheets. The NiS2/MXene nanocomposites were then modified on PP separators to form a thin layer of 8 μm in the Li-S batteries, which exhibit the significant characteristics of capture and conversion of LiPSs, as well as highly-efficient transferring pathways of electron/Li+ via the synergetic effect of NiS2 and MXene from their strong chemisorption abilities, rich catalyzing active sites, and high electron conductivity, accelerating to the redox reaction kinetics of LiPSs. Consequently, these Li-S batteries by using the modified PP separators show a high reversible capacity of 805.1 mAh/g at 0.2 C after 200 cycles. Even at 2 C, it still exhibits a low capacity decay of 0.038 % per cycle after long-term stable 1000 cycles. This work proves that the developing multifunctional separators are efficient strategies for high performance Li-S batteries.

Toward Sustainable Li-S Battery Using Scalable Cathode and Safe Glyme-Based Electrolyte.

The search for safe electrolytes to promote the application of lithium-sulfur (Li-S) batteries may be supported by the investigation of viscous glyme solvents. Hence, electrolytes using nonflammable tetraethylene glycol dimethyl ether added by lowly viscous 1,3-dioxolane (DOL) are herein thoroughly investigated for sustainable Li-S cells. The electrolytes are characterized by low flammability, a thermal stability of ∼200 °C, ionic conductivity exceeding 10-3 S cm-1 at 25 °C, a Li+ transference number of ∼0.5, electrochemical stability window from 0 to ∼4.4 V vs Li+/Li, and a Li stripping-deposition overpotential of ∼0.02 V. The progressive increase of the DOL content from 5 to 15 wt % raises the activation energy for Li+ motion, lowers the transference number, slightly limits the anodic stability, and decreases the Li/electrolyte resistance. The electrolytes are used in Li-S cells with a composite consisting of sulfur and multiwalled carbon nanotubes mixed in the 90:10 weight ratio, exploiting an optimized current collector. The cathode is preliminarily studied in terms of structure, thermal behavior, and morphology and exploited in a cell using standard electrolyte. This cell performs over 200 cycles, with sulfur loading increased to 5.2 mg cm-2 and the electrolyte/sulfur (E/S) ratio decreased to 6 μL mg-1. The above sulfur cathode and the glyme-based electrolytes are subsequently combined in safe Li-S batteries, which exhibit cycle life and delivered capacity relevantly influenced by the DOL content within the studied concentration range.

Application of nanomaterials in lithium-sulfur batteries and lithium-air batteries

Because of its high voltage, high specific energy, and other good qualities, lithium-ion batteries have recently become one of the most popular studies. In the context of nanomaterials, this research investigates the function of nanomaterials in the application of lithium-sulfur and lithium-air batteries. In addition to examining the classification, benefits and drawbacks, uses and advances of nanomaterials, this essay also examines the fundamentals of two batteries, as well as the uses of nanomaterials in both types of batteries. The results show that nanomaterials have a very large surface area and a sudden change in material properties because of their arrival at the nanoscale, and have very good mechanical and optical properties, which have a very good contribution to the performance of the batteries. However, it was discovered that nanomaterials in lithium-ion battery applications still have issues, such as high cost and challenging synthesis procedures, through the investigation of several nanomaterials in two batteries. In addition to offering fresh perspectives for society, this study seeks to better understand the economic and safety issues associated with two batteries used in practical production.

Ni@O-doped carbon Mott-Schottky heterojunctions to enhance sulfur conversion kinetics

The practical application of lithium-sulfur batteries (LSBs) is hindered by the sluggish redox kinetics of polysulfides. The authors propose that a Ni@OC Mott-Schottky heterojunction catalytically accelerates sulfur conversion reactions. The experimental results reveal that benefitting from a self-generated built-in electric field, the charge redistribution at the Ni@OC heterointerface accelerates electron transfer and enhances catalytic activity contributing to the conversion kinetics of polysulfides. Therefore, the cells assembled with Ni@OC heterojunction display an excellent rate performance (the capacity 640.4 mAh∙g−1 at 3 C) and a high capacity of 1026.6 mAh∙g−1 under the lean electrolyte (E/S = 5.0 μL∙mg−1) conditions. The proposed Mott-Schottky heterostructure provides a favorable reference and advanced guidance for high-capacity lithium-sulfur batteries.

Carbon nanofibers implanted porous catalytic metal oxide design as efficient bifunctional electrode host material for lithium-sulfur battery

The shuttling effect of lithium polysulfides (LiPSs) and uncontrolled dendrite formation of metal lithium anode are the two critical obstacles hindering the commercial application of lithium-sulfur (Li-S) batteries. Herein, a bifunctional electrode host design consists of carbon nanofibers implanted ordered porous Co-decorated Al2O3 supported on carbon nanotube film (CNTF) is proposed to address these problems. As cathode sulfur host material, benefiting from the synergistic effect of porous Co-Al2O3 and the embedded CNFs, the CNFs/Co-Al2O3@CNTF exhibits excellent conductivity, efficient LiPSs confinement and catalytic conversion performance. It shows a high initial capacity of 1165 mAh g−1 at 0.2 C, and holds a capacity of 594 mAh g−1 even up to 3 C. When serves as anode, the CNFs/Co-Al2O3@CNTF electrode exhibits excellent Li+ diffusion performance and uniform lithium growth behavior, achieving a dendrite-free lithium electrode. The anode also shows good cycle stability during an ultra-long cycle time of 1000 h. A flexible pack cell assembled from CNFs/Co-Al2O3@CNTF electrodes delivers a specific capacity of 972 mAh g−1 with capacity retention rate of 86.4% at 0.1 C.

A ZIF-8 modified aramid nanofiber separator against the shuttle effect for high performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are considered the most promising energy storage systems due to their high specific capacity and energy density. However, the practical application of lithium-sulfur batteries has been hampered by capacity loss due to the shuttle effect and serious safety issues due to the flammability and shrinkage of commercial diaphragms at high temperatures. Herein, we designed a separator by adding ZIF-8 nanoparticles to aramid nanofibers named ZIF-8/ANF. ANF has high flame retardant property and high mechanical strength to prevent separators failure at high temperature, preventing lithium dendrites from punctured separators and causing short circuit. ZIF-8 has the porous structure, while exposing abundant metal nodes acting as active sites, which can effectively adsorb polysulfides and inhibit the shuttle effect. As a result, the Li-S batteries with ZIF-8/ANF separators exhibit high specific discharge capacity and cycle performance. The Li-S batteries show a high initial specific capacity of 1178.3 mAh g−1 at 0.1 C and 525.9 mAh g−1 after 400 cycles. In addition, they also exhibit discharge capacity is 825.6 mAh g−1 at 0.2 C with the loading of 3.5 mg cm−2. This work offers a guidance for safe and high-performance Li-S batteries.

Facile synthesis of MoS2 confined in yolk-shell hollow mesoporous carbon spheres with enhanced polysulfide binding for high-rate Li-S batteries

Lithium-sulfur (Li-S) batteries are one of the most potential energy storage systems because of their high theoretical density, environmental friendliness. However, the practical application of Li-S batteries is currently hampered by several intrinsic problems including the shuttle effects of polysulfides and sluggish electrode reaction kinetics. Herein, a flower-like MoS2 nanosheets confined and in situ grown inside yolk-shell hollow mesoporous carbon spheres (abbreviated as MoS2 @YHMCs) was fabricated as advanced sulfur immobilizer, which can effectively inhibit shuttle effect and conversion of polysulfides. The yolk-shell hollow mesoporous carbon spheres can restrain the volume variation during lithiation-delithiation processes, expose abundant active interfaces and furnish a shortened ion/electron transmission route for facilitated redox reactions. Furthermore, the few layered MoS2 nanosheets have strong LiPS adsorption and catalyzation, thereby achieving rapid redox conversion and enhanced reaction kinetics. Owing to these structural advantages, the delicately-designed MoS2 @S@YHMCs cathode shows good Li-S battery performance, i.e., high initial discharge capacity (1145 mAh g−1), desirable rate capability (770 mAh g−1 at 4 C), and superior cycling performance (583 mAh g−1 after 200 cycles at 1 C), suggesting great application prospects in the development of Li-S batteries.

Interfacial Engineering of Ru Nanocluster-Modified TiO2 Nanotube-Assisted Regulation of Lithium Polysulfide Reactions.

The inhibition of lithium polysulfide (LiPS) diffusion and the acceleration of reaction kinetics are two major challenges for the practical application of lithium-sulfur (Li-S) batteries. Herein, through an interface engineering strategy, a multifunctional sulfur host based on Ru nanocluster-modified TiO2 nanotubes (TiO2-Ru) was designed. The TiO2-Ru interface field effect, combined with the hollow nanotube structure and the strong chemical action of TiO2, enhanced the LiPS trapping ability and inhibited the "shuttle effect". Furthermore, the high catalytic activity of Ru nanoclusters reduced the energy barrier of multistep LiPS reactions, thus speeding up the electrode kinetics. As a result, the TiO2-Ru-based composite sulfur cathode delivered excellent electrochemical performance, including an extremely low capacity loss of ∼0.015% per cycle and an increased areal capacity of ∼6.1 mAh cm-2 at 4.8 mg cm-2. This work contributes to a better sulfur cathode design from insights into morphology and phase interface engineering.

Tuning the localized dissolution environment of polysulfides for practical Li-S cells

The shuttle effect of soluble polysulfides is one of the main reasons for the poor cycling performance, which greatly impedes the practical application of lithium-sulfur (Li-S) batteries. In this context, we report a novel design of sulfur cathode structure by regulating the distribution of PEO on the surface of C/S particles to extend the stable cycle life of practical Li-S cells. The in-situ dissolution of PEO changes the localized solution environment around C/S particles and suspends the diffusion of polysulfides (LiPSs), while the large number of mesopores retained inside C/S particles can ensure the good infiltration of electrolyte and act as a container for LiPSs. With this strategy, the cycle performance of the high sulfur loading (∼4 mg cm−2) Li-S pouch cell is significantly improved, with a discharge-specific capacity above 900 mAh g−1 and a capacity retention rate of 91.68% for 70 cycles. In addition, the rate performance of pouch cells is quite significant due to the promotion of local kinetic conversion (736.4mAh g−1 at 2C). At last, the Ah-scale Li-S pouch cell exhibits excellent capacity (above 1000 mAh g−1), low fading (0.16% per cycle), and high power capability. This work offers a new perspective for the design of sulfur cathode structures and promotes the scale-up of lithium-sulfur cells for practical applications.

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.

A Triptycene-Based Layered/Flower-Like 2D Conductive Metal-Organic Framework with 3D Extension as an Electrode for Efficient Li Storage.

2D metal-organic frameworks (2D MOFs) with π conjugation have attracted widespread attention in the field of lithium storage due to their unique electron transfer units and structural characteristics. However, the periodic 2D planar extension structure hides some active sites, which is not conducive to the utilization of its structural advantages. In this work, a series of triptycene-based 2D conductive MOFs (M-DBH, M = Ni, Mn, and Co) with 3D extension structures are constructed by coordinating 9,10-dihydro-9,10-[1,2]benzenoanthracene-2,3,6,7,14,15-hexaol with metal ions to explore their potential applications in lithium-ion and lithium-sulfur batteries. This is the first study in which 2D conductive MOFs with the 3D extended molecule are used as electrode materials for lithium storage. The designed material generates rich active sites through staggered stacking layers and shows excellent performance in lithium-ion and lithium-sulfur batteries. The capacity retention rate of Ni-DBH can reach over 70% after 500 cycles at 0.2 C in lithium-ion batteries, while the capacity of S@Mn-DBH exceeds 305 mAhg-1 after 480 cycles at 0.5 C in lithium-sulfur batteries. Compared with the materials with 2D planar extended structures, the M-DBH electrodes with 3D extended structures in this work exhibit better performance in terms of cycle time and lithium storage capacity.

Improve the anchoring of 2D Ti2O electride in lithium-sulfur batteries through surface modification strategy: First principle study

Lithium-sulfur battery stands out in the next generation of rechargeable lithium batteries because of its high theoretical capacity (1675 mAh/g) and energy density (2600 Wh/kg). However, the shuttle effect seriously hinders the development and practical application of lithium-sulfur batteries. Here, we systematically studied the anchoring performance of two-dimensional (2D) Ti2O electride modified with N, O, F, P, S and Cl atoms in this paper. It was found that Ti2OF2 and Ti2OS2 showed excellent adsorption energy (1.21–2.62 eV), and their adsorption systems remained stable without obvious distortion, after the first principle calculation of the adsorption structure of Ti2OM2. In addition, Ti2OF2 and Ti2OS2 not only have excellent conductivity but maintain excellent conductivity after adsorbing Li2Sn, which indicates that they can effectively inhibit the shuttle effect and promote the performance of the battery.

A binder-free dry coating process for high sulfur loading cathodes of Li–S batteries: A proof-of-concept

A promising candidate for next-generation energy storage is the lithium-sulfur battery (LSB) due to its high capacity and low-cost active material (sulfur). However, the practical application of LSBs is challenged by poor cycling life and low sulfur loading. Herein, a proof-of-concept for manufacturing high load electrodes with a low-cost dry (solvent-free) coating process with a reduced carbon footprint is introduced and investigated. This process is often based on fluoropolymer-based binder additives with health and environmental concerns. Therefore, this study presents the concept of a binder-free dry coating process using sulfur/carbon black (S/CB) composites derived from a straight-forward dispersive mixing process. The electrodes are fabricated by a hot-pressing process, taking advantage of sulfur melting into a carbon matrix. To determine the process-structure-property relationships of the resulting powders, electrodes and cells, a novel structure determination by thermogravimetric analysis was used. Mixing time turns out to be an important factor, which has a significant effect on the electrode performance. The cells assembled with electrodes (⁓4.5 mgS cm−2) made from optimized powder mixtures showed a high specific capacity of about 800 mAh gS−1, and a relatively improved C-rate capability.

Adsorption-catalysis synergy within pyrrolic-N-rich carbon nanosheets: Propelling electrochemical kinetics and shielding polysulfides for lithium-sulfur batteries

The practical applications of lithium-sulfur (Li-S) batteries are rather limited by the shuttle effect of lithium polysulfides (LiPSs) and sluggish redox reaction kinetics. Here, a kind of pyrrolic-N-rich carbon nanosheets (Npr-CNs) are prepared by introducing melamine cyanurate (MCA) into the carbonization process of polyacrylonitrile (PAN). As a mediator in Li-S batteries, hierarchical pores, dominant pyrrolic-N-doping, disorder/defective structures and unique electronic states endow Npr-CNs with synergistic adsorption-catalysis function for S species. Specifically, they can effectively inhibit LiPSs shuttle, catalyze the conversion of both liquid-phase LiPSs and solid-phase Li2S, reduce the charge transfer resistance and enhance Li-ions migration rate. Hence, it can make the Li-S batteries deliver excellent rate performance and cycling stability. The battery can reach ultrahigh discharge capacity of 932.0 mAh g−1 at the beginning under current density of 1C and even liberate a capacity as high as 1109.4 mAh g−1 at 0.2C with high sulfur loading of 3.8 mg cm−2.

Surface design for high ion flux separator in lithium-sulfur batteries

Addressing the shuttle effect is a critical challenge in realizing practical applications of lithium-sulfur batteries. One promising avenue refers to the surface modification of separators, transitioning them from closed to open structures. In the current investigation, a high ion flux separator was devised by means of MnO2 self-assembly onto a Porous Polypropylene (PP) separator, subsequently coupling it with biochar. The separator exhibited favorable ion and electronic conductivity. Moreover, it adeptly captured and transformed polysulfides into Li2S2/Li2S, cyclically curbing the mobility of Polysulfide lithium (LiPSs). In addition, this augmentation in the kinetic conversion of LiPSs during the electrochemical process translated into an impressive discharge specific capacity and area capacity of 939 mAh/g and 4 mAh cm−2, respectively. Moreover, this innovative design methodology provides an alternative avenue for future separator designs within lithium-sulfur batteries.