High-performance Lithium-sulfur Batteries Research Articles

Dual-atoms iron sites boost the kinetics of reversible conversion of polysulfide for high-performance lithium-sulfur batteries

Atomically dispersed metal catalysts have offered significant potential for accelerating sluggish kinetics of lithium polysulfides conversion and inhibiting the shuttle effect, so as to achieve the long-life cycle and high-rate performance of lithium sulfur batteries. However, the end-on adsorption structure between single metal site and polysulfide limits the adsorption capacity and catalytic activity of single atom catalysts. Here, we construct dual-atoms iron sites on nitrogen doped graphene to serve as highly efficient catalyst for lithium sulfur batteries. As expected, the dual-atoms sites can firmly bind polysulfides by forming double Fe-S bonds between polysulfides and the two adjacent iron atoms. Such double-bond adsorption structure is also favorable for electron transfer and polysulfides activation, resulting in reducing the energy barrier and accelerating the reaction kinetics. As a result, the as-obtained dual-atoms iron catalyst can effectively alleviate the shuttle effect and improve the utilization of active sulfur, thus the batteries present high initial capacity of 1615 mAh g−1 at 0.05 C and long-cycle life with a decay rate per cycle as low as 0.015% at 2C over 1000 cycles.

Ni-plated viscose-based carbon fibers/biomass-derived hierarchical porous carbon for high-performance lithium-sulfur battery free-standing cathodes

Developing high-performance lithium-sulfur batteries has become an important strategy to achieve sustainable development. In this study, a novel and high-performance stand-alone cathode material, containing Ni-plated viscose-based carbon fiber (VBCF/Ni) and hierarchical porous carbon (HPC), was prepared. The conductivity, adsorption and catalytic effect of the VBCF substrate, on the Li2S/LiPSs, were improved after Ni-plating. HPC, containing micro- and mesopores, was obtained by carbonizing edible sweet potato flour and served as a direct host for sulfur (HPC@S). The large specific surface area (386.8 m2 g−1) and pore volume (0.4556 cm3 g−1) of HPC were suitable for achieving a good sulfur loading and LiPSs adsorption. Due to the synergistic effect of the polar metallic Ni and non-polar carbon groups, the performance of the VBCF/Ni/HPC@S cathode was significantly improved. The obtained cell showed a reversible capacity of 1206 mAh g−1 at 0.1 C, maintained 892.2 mAh g−1 after 200 cycles at a rate of 0.2 C, and showed a capacity retention rate of 82.6%.

Rational design of MoSSe nanosheets on N-doped carbon hollow spheres for accelerating polysulfide redox kinetics of high-performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries with high theoretical energy densities offer a promising alternative for next-generation energy storage. However, the poor conductivity, shuttle effect of lithium polysulfides (LiPSs), and large volume expansion upon cycling hinder their application. Hollow nanostructures can play an important role in achieving high sulfur loading, buffering volume expansion, and inhibiting LiPSs shuttling. In this work, MoSSe nanosheets grown on N-doped carbon hollow spheres (MoSSe/NC) are used as both sulfur host and separator to achieve catalytic adsorption and conversion of LiPSs. As a sulfur host, MoSSe/NC can enhance electron/ion transport and alleviate the volume expansion of sulfur during cycling, further accelerating the redox kinetics. The MoSSe/NC-modified separator can also induce interfacial charge modulation and expose more active sites, promoting rapid anchoring and conversion of LiPSs and uniform deposition of Li2S. Theoretical calculations and experiments verify that MoSSe/NC can catalyze the conversion of LiPSs, inhibit the shuttle effect, and effectively improve the electrochemical properties of sulfur. Therefore, the MoSSe/NC based Li-S battery exhibits high initial capacity (1455 mAh g−1), excellent rate performance (891 mAh g−1 at 2 C), and good cycling stability (0.049% capacity decay rate at 800 cycles at 1 C).

Mo2N quantum dots decorating N-doped carbon nanosheets for kinetics-enhanced Li-S batteries

Lithium-sulfur (Li-S) batteries face two main challenges, which are the severe shuttle effect of lithium polysulfides (LiPSs) and the slow redox kinetics of LiPSs. Herein, monodispersed Mo2N quantum dots decorating N-doped carbon nanosheets (Mo2N@NCNS) are rationally engineered via a simple and cost-effective method and used as an effective host for sulfur in high-performance Li-S batteries. Mo2N@NCNS presents enhanced intrinsic conductivity, superior catalytic capability, and improved LiPSs redox kinetics. The 3D N-doped carbon nanosheet networks endowed with abundant catalytic sites can heighten physically confined and chemically adsorptive LiPSs by strongly polar-polar interactions, further regulating the disordered motion of LiPSs. In the meanwhile, the highly dispersed Mo2N quantum dots with powerful adsorptive-catalytic properties anchor the soluble LiPSs and facilitate high-efficiency diffusion-conversion kinetics for the nucleation and deposition of Li2S2/Li2S, thus promoting the complete utilization of sulfur and the overall enhancement of electrochemical performance. Owing to these fascinating features, the Mo2N@NCNS-based sulfur cathodes demonstrate substantial enhancement in electrochemical performance, including remarkable capacity performance (1221 mAh g−1 at 0.2 C) and exceptional cyclability over 800 cycles at 2 C with a minimal decay rate (0.03 % per cycle). This work highlights the great potential of rational design of advanced composite materials for promoting the practical viability of Li-S batteries in energy storage systems.

Integrated interconnected porous and lamellar structures realized fast ion/electron conductivity in high-performance lithium-sulfur batteries

The practical application of high-energy-density lithium-sulfur (Li-S) batteries have been highly praised for energy storage devices, while are largely hindered by the “shuttling effect”. Herein, core-shell carbon spheres composed of interlinked porous core and lamellar shell were designed to restrain the polysulfide shuttling. The microporous structure with pore size of around 1 nm effectively trap lithium polysulfides. Furthermore, the interconnected porous core shortens the ion transfer distance and the lamellar carbon shell endows the carbon spheres with fast electron conduction, finally facilitating polysulfide conversion kinetics. Therefore, the Li-S batteries with the carbon spheres as the interlayer show high discharge specific capacity of 1002 mAh/g at 2 C with 574 mAh/g remaining after 600 cycles, and high areal capacity of 5.48 mAh/cm2 with sulfur loading of 4.67 mg/cm2 at 0.1 C. The corresponding pouch cells also exhibit stable cycling stability with an initial discharge specific capacity of 1082 mAh/g at 0.1 C.

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.

Hollow multishelled structural TiN as multi-functional catalytic host for high-performance lithium-sulfur batteries

Hollow multishelled structural TiN as multi-functional catalytic host for high-performance lithium-sulfur batteries

Bimetallic sulfides heterostructure efficient adsorption and catalytic of polysulfides for high-performance lithium-sulfur batteries

Bimetallic sulfides heterostructure efficient adsorption and catalytic of polysulfides for high-performance lithium-sulfur batteries

Fluoride-samarium(III) doped hierarchically porous carbon nanofibers as thin separator coating layer with excellent adsorption and outstanding catalysis of lithium polysulfide for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are promising for next-generation energy storage due to their high energy density and low cost. However, challenges such as the “shuttle effect,” slow reaction kinetics, and lithium dendrite growth hinder their performance. In this study, we developed fluoride-samarium(III) doped hierarchically porous carbon nanofibers (SmF3-PCNFs) and coated them onto separators. These three-dimensional porous carbon networks confined LiPSs, while polar SmF3 nanoparticles acted as efficient chemical anchors and catalysts. Simultaneously, the polar fluoride interfaces between the SmF3-PCNFs and cathode also can accelerate the transport of lithium ions and enhance the adhesion between them, enabling them to accommodate the huge volume changes of the sulfur cathode during cycling and improve long-cycle stability. Moreover, the modified separator with excellent lithium affinity also enables uniform lithium deposition to reduce lithium dendrite growth. Combining these advantages, the assembled Li-S battery with SmF3-PCNFs modified separator exhibits a high initial discharge specific capacity of 1068.2 mAh g−1 and retains a capacity of 655.3 mAh g−1 after 750 cycles (with a decay rate of only 0.05 % per cycle), and the Coulombic efficiency remains above 93 %. This work will pave a new design path for the preparation of modified separators in high-performance Li-S batteries.

3D Electrode architecture of high surface area carbon-sulfur composite as high energy density cathode for lithium-sulfur battery

High-performance lithium-sulfur (Li-S) battery is a potential candidate for next-generation energy storage systems to mitigate the ever-rising energy demand. The low cost of sulfur, eco-friendliness, and high energy density compared to the emerging LIBs (450 Wh kg−1 for Li-S batteries vs. 150–250 Wh kg−1 for LIBs) inspires the research on Li–S technology. In this work, carbon fiber-based free-standing electrodes are fabricated using a high surface area carbon-sulfur (HSAC-S) composite synthesized by the melt-diffusion method. The porous carbon host facilitates high sulfur loading in the void spaces and benefits the electrolyte infiltration and Li-ion diffusivity. Electrochemistry reveals that HSAC-S@CF exhibits an enhanced discharge capacity of 1000 mAh g−1 (750 mAh g−1 for HSAC-S@Al) in the 2nd cycle and maintains 620 mAh g−1 capacity till the 100th cycle. In comparison, HSAC-S@Al delivers 350 mAh g−1 capacity at the 80th cycle at a current density of 100 mA g−1. Besides, at 200 mA g−1, the free-standing electrode HSAC-S@CF delivers an initial capacity of 600 mAh g−1 (498 mAh g−1 HSAC-S@Al) and retains 497 mAh g−1 till the 100th cycle with 83 % capacity retention (60 % HSAC-S@Al). HSAC-S@CF displays good C-rate performance at a higher current density of 1 A g−1 (408 mAh g−1) and 1.5 A g−1 (346 mAh g−1). The conductive CF backbone provides mechanical stability, accommodates volume changes, and reduces particle agglomeration. The internal void spaces of the CF matrix act as a reservoir for polysulfides and minimize the shuttling effect. This work represents an effective cathode modification approach to understand the impact of high surface area carbon additives on free-standing 3D electrode architecture and its interaction with sulfur for improving the capacity and cycling stability in Li-S batteries.

Dually Sulphophilic Chromium Boride Nanocatalyst Boosting Sulfur Conversion Kinetics Toward High-Performance Lithium-Sulfur Batteries.

The sluggish kinetics of sulfur conversions have long been hindering the implementation of fast and efficient sulfur electrochemistry in lithium-sulfur (Li-S) batteries. In this regard, herein the unique chromium boride (CrB) is developed via a well-confined mild-temperature thermal reaction to serve as an advanced sulfur electrocatalyst. Its interstitial-alloy nature features excellent conductivity, while the nano-lamination architecture affords abundant active sites for host-guest interactions. More importantly, the CrB nanocatalyst demonstrates a dual sulphophilicity with simultaneous Cr─S and B─S bondage for establishing strong interactions with the intermediate polysulfides. As a result, significant stabilization and promotion of sulfur redox behavior can be achieved, enabling an excellent Li-S cell cyclability with a minimum capacity fading rate of 0.0176% per cycle over 2000 cycles and a favorable rate capability up to 7C. Additionally, a high areal capacity of 5.2mAhcm-2 , and decent cycling and rate performances are still attainable under high sulfur loading and low electrolyte dosage. This work offers a facile approach and instructive insights into metal boride sulfur electrocatalyst, holding a good promise for pursuing high-efficiency sulfur electrochemistry and high-performance Li-S batteries.

NiSe nanoparticles decorated corn stalk derived 2D carbon nanosheet as separator modifier for high-performance lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries are considered as the most promising successors of lithium-ion batteries, however, the shuttle effect and sluggish reaction kinetics are the biggest obstacles hindering their commercialization. In this work, a kind of NiSe nanoparticles embedded in corn stalk-derived two-dimensional (2D) porous carbon nanosheet (NiSe@CSC) is constructed as a separator modifier for advanced Li–S batteries. The rich pore structure of the corn stalk-derived carbon nanosheets enables uniform distribution of NiSe and provides more deposition sites for lithium polysulfides (LiPS). Electrochemical analyses show that NiSe increases the affinity for LiPS to suppress the shuttle effect, thereby effectively preventing the corrosion of polysulfide on the lithium anode. NiSe@CSC is found to accelerate the redox conversion of sulfur species in the kinetic study. Consequently, the assembled Li–S cells with NiSe@CSC coating layer exhibit a high-rate performance of 710 mAh g−1 at 3 C and a low capacity attenuation rate of 0.046% per cycle after 800 cycles at 1 C. Furthermore, it can still maintain 2.8 mAh cm−2 at 0.5 C in near-commercial application scenarios of 4.1 mg cm−2 sulfur loading. The NiSe@CSC-based Li–Li symmetric cells also demonstrate stability and low overpotential in protecting the lithium anode. This combination of renewable biomass-based carbons and transition metal selenides enriches the exploration of biomass materials in separators and provides new ideas for designing practical Li–S batteries.

Clarifying the Role of Ordered Mesoporous Carbon on a Separator for High-Performance Lithium–Sulfur Batteries

Clarifying the Role of Ordered Mesoporous Carbon on a Separator for High-Performance Lithium–Sulfur Batteries

In-situ constructing hetero-structured Mo2C-Mo2N embedded in carbon nanosheet as an efficient separator modifier for high-performance lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are promising electrochemical energy storage devices. However, the shuttle effects and slow conversion kinetics of lithium polysulfides (LiPSs) still impede the practical application of LSBs. Herein, with the assistance of g-C3N4, a hetero-structured Mo2C-Mo2N embedded in the nitrogen-doped carbon sheets composite (Mo2C-Mo2N/C) is facilely in-situ synthesized. The g-C3N4 not only acts as the nitriding reagent for the heterostructure formation, but also is the structure-directing reagent for the formation of two-dimensional structures. More interestingly, Mo2C-Mo2N/C is also employed as a modifier of separators for LSBs. As evidenced experimentally and theoretically, the hetero-structured Mo2C-Mo2N exhibits a strong adsorption ability to LiPSs and concurrently offers a built-in electric field inside the heterostructure that ensures the fast conversion of LiPSs, thus significantly suppressing the shuttle effect and accelerating the electrochemical kinetics of LSBs. Therefore, the prepared LSBs with the Mo2C-Mo2N/C modified separator deliver a discharge specific capacity of 1404 mAh/g at 0.1 C and 660 mAh/g at 4 C, and achieve 1000 stable cycles at 1 C, with a capacity decay rate of only 0.028% per cycle. This study not only provides an efficient strategy for synthesizing hetero-structured materials but also sheds new light on the design of functional separators for high-performance and long-life cycle LSBs.

CoS2@SC modified separator for high-performance lithium-sulfur batteries: suppression of polysulfide shuttling

ABSTRACT Due to their high energy density and cost-effective electrode materials, lithium sulfur batteries (LSBs) have been considered as one promising candidate of energy devices. However, the practical application is impeded by the shuttle effect of lithium polysulfides and slow redox kinetics of electrode. Here, we report a successful synthesis of CoS2@SC composite material via in-situ growth and sulfuration pyrolysis method and prepared CoS2@SC modified separator. The carbon matrix derived from sucrose carbonization with a porous structure promotes the uniform distribution of active adsorption sites. According to Lewis acid–base interaction, CoS2@SC separator exhibits strong chemisorption of lithium polysulfides, reducing the loss of active material during cycling. Furthermore, the enhanced wettability of the CoS2@SC separator with the electrolyte accelerates the ion transfer, improving the reaction kinetics. Compared with the blank separator, the cell with CoS2@SC separator has an initial specific capacity of 1135.5 mAh g−1 and notably, the capacity decay rate of the modified battery is only 0.052% per cycle after 800 long cycles at 0.5 C. This unique attribute ensures enhanced stability and durability of the battery system. Consequently, LSBs with the CoS2@SC separator exhibit an improved electrochemical performance.

The catalytic role of surface Co(PO3)2 on CoP for high-performance lithium-sulfur batteries

Electrocatalysts is maturely explored to strengthen the conversion kinetics for lithium polysulfides (LiPSs) and avoid the shuttle effect. However, the perspicuous role of surface oxidation species electrocatalysts on LiPSs conversion kinetics is still confused and needs to be uncovered. Here, we prepared progressively surface oxidized CoP/CNT (OCoP/CNT) and confirmed the formation of surface amorphous Co(PO3)2. The generation of surface Co(PO3)2 induces the phosphorous vacancy synergistically improving the catalytic conversion kinetics of OCoP/CNT functionalized separator towards LiPSs. Furthermore, the In-situ Raman spectra is adopted to disclose the key catalytic role of Co(PO3) on OCoP/CNT. With an E/S ratio of 15 µL mg−1, the lithium sulfur (Li-S) battery with OCoP/CNT functionalized separator showcases amazing and satisfying high-rate performance, especially at 2C and 3C. This study would get across the full comprehension of the catalytic role of the surface oxidation species and guide the new approach for the metal-based electrocatalyst of Li-S battery.

Lithium phosphate incorporated carbon nanotube interlayer as an efficient polysulfide immobilizer for high performance lithium sulfur batteries

Lithium-sulfur (Li-S) batteries are the potential alternative for the lithium-ion batteries, owing to their remarkable energy density and specific capacity. Nevertheless, the lower utilization of active materials and the “shuttle effect” have impeded their widespread commercialization. To address these hurdles, a pioneering method has been proposed, involving a lithium phosphate-incorporated multi-walled carbon nanotube (Li3PO4@MWCNT) interlayer. The Li3PO4@MWCNT interlayer primarily serves as a physical barrier against polysulfide shuttling. Its highly conductive cross-link structure enables it to adsorb chemically derived lithium polysulfides (LiPS) and catalyze their conversion by incorporating Li3PO4 into the MWCNT matrix. This synergistic effect of immobilizing and converting LiPS results in a significant reduction in the “shuttle effect,” leading to enhanced sulfur utilization. The experimental results evidence the enhanced performance of the Li-S cells, with a capacity of 381 mAh g−1 at 0.1C and high C-rate performance of 393 mAh g−1 at 1C.

Co/CoS2 Heterojunction Embedded in N, S-Doped Hollow Nanocage for Enhanced Polysulfides Conversion in High-Performance Lithium-Sulfur Batteries.

Modulating the electronic configuration of the substrate to achieve the optimal chemisorption toward polysulfides (LiPSs) for boosting polysulfide conversion is a promising way to the efficient Li-S batteries but filled with challenges. Herein, a Co/CoS2 heterostructure is elaborately built to tuning d-orbital electronic structure of CoS2 for a high-performance electrocatalyst. Theoretical simulations first evidence that Co metal as the electron donator can form a built-in electric field with CoS2 and downshift the d-band center, leading to the well-optimized adsorption strength for lithium polysulfides on CoS2 , thus contributing a favorable way for expediting the redox reaction kinetics of LiPSs. As verification of prediction, a Co/CoS2 heterostructure implanted in porous hollow N, S co-doped carbon nanocage (Co/CoS2 @NSC) is designed to realize the electronic configuration regulation and promote the electrochemical performance. Consequently, the batteries assembled with Co/CoS2 @NSC cathode display an outstanding specific capacity and an admirable cycling property as well as a salient property of 8.25mAhcm-2 under 8.18mgcm-2 . The DFT calculation also reveals the synergistic effect of N, S co-doping for enhancing polysulfide adsorption as well as the detriment of excessive sulfur doping.

Single-Atomic Dispersion of Fe and Co Supported on Reduced Graphene Oxide for High-Performance Lithium-Sulfur Batteries.

High theoretical energy density and low cost make lithium-sulfur (LSB) batteries a promising system for next-generation energy storage. LSB performance largely depends on efficient reversible conversion of elemental sulfur to Li2S. Here, well-designed sulfur host materials including Fe or Co single atoms embedded on N-doped reduced graphene oxide (MNC/G with M = Fe or Co) are proposed to tackle the LSB challenges and enhance the electrochemical performance. Using a combination of Mössbauer spectroscopy and high-resolution scanning electron microscopy, the atomic dispersion of Co and Fe was revealed up to relatively high mass loadings. After optimization of the electrolyte/sulfur (E/S) ratio, FeNC/G shows the most promising cycle performance combining a constant high discharge capacity at low E/S values with the lowest polarization. In particular, the material FeNC/G@S with a high sulfur loading (9.4 mg cm-2) delivers a high area capacity of 7.7 mAh cm-2 under lean electrolyte conditions (6 mL g-1).

Rational design of a functional interlayer to simultaneously suppress lithium polysulfides shuttling and facilitate Li-ion migration for high-performance Li-S battery

Lithium-sulfur (Li-S) battery has been considered to be the most promising next-generation secondary battery system, but the shuttle effect of lithium polysulfides (LiPSs) and sluggish redox kinetics of LiPSs conversion processes still hinder its commercial application. Herein, a honeycomb-like structured and dense layer coated interlayer with Co nanoparticles uniformly dispersed was fabricated via a modified phase inversion method followed by carbonization. This interlayer can suppress the LiPSs shuttling by physically blocking the diffusion of LiPSs and chemically capturing and accelerating the conversion of LiPSs due to the high catalytic activity of Co nanoparticles. Meanwhile, the abundant lithiophilic pyridinic N sites can also facilitate Li+ migration, which further promotes the reaction kinetics of LiPSs conversion. Consequently, the Li-S battery assembled with this interlayer can exhibit an excellent specific capacity of 586.6 mAh/g after 400 cycles at 4.0 C with a low decay rate of 0.10 %. Even when the sulfur loading is elevated to 5.1 mg cm−2, this battery can still maintain the specific capacity of 646.0 mAh/g after 100 cycles at 0.2 C. This work demonstrates the importance and potential of the rational design of interlayer structure and composition in improving the overall Li-S battery performance.