Lithium-sulfur batteries(LSBs)are one of the most promising energy storage devices because of their high theoretical energy density;however,inherent issues including poor electrical conductivity and severe dissolution...Lithium-sulfur batteries(LSBs)are one of the most promising energy storage devices because of their high theoretical energy density;however,inherent issues including poor electrical conductivity and severe dissolution of S and its discharged products hinder their practical applications.MXenes have metallic conductivity,ultra-thin two-dimensional(2D)structures,rich surface functional groups,and macrostructural adjustability and have been widely used to design advanced sulfur hosts.3D network structures assembled by 2D MXene nanosheets have shown superior performance for improving reaction kinetics,accommodating and dispersing sulfur at the micro-/nanoscale,and capturing polysulfides due to their porous interconnected structure.Herein,the applications of MXene architectures related to 2D layered structures,3D multilayered structures,and 3D spherical structures as sulfur hosts are reviewed.The structure-performance relationship,challenges for current designs,and opportunities for future 3D architectures for LSBs are also analyzed.展开更多
The sluggish redox kinetics and shuttle effect of soluble polysulfides intermediate primarily restrict the electrochemical performance of lithium–sulfur(Li–S) batteries. To address this issue, rational design of hig...The sluggish redox kinetics and shuttle effect of soluble polysulfides intermediate primarily restrict the electrochemical performance of lithium–sulfur(Li–S) batteries. To address this issue, rational design of high–efficiency sulfur host is increasingly demanded to accelerate the polysulfides conversion during charge/discharge process. Herein, we propose a macro–mesoporous sulfur host(Co@NC), which comprises highly dispersed cobalt nanoparticles embedding in N–doped ultrathin carbon nanosheets. Co@NC is simply synthesized via a carbon nitride–derived pyrolysis approach. Owing to the highly conductive graphene–like matrix and well defined porous structure, the designed multifunctional Co@NC host enables rapid electron/ion transport, electrolyte penetration and effective sulfur trapping. More significantly,N heteroatoms and homogeneous Co nanocatalysts in the graphitic carbon nanosheets could serve as chemisorption sites as well as electrocatalytic centers for sulfur species. These Co–N active sites can synergistically facilitate the redox conversion kinetics and mitigate the shuttling of polysulfides, thus leading to improved electrochemical cycling performance of Li–S batteries. As a consequence, the S/Co@NC cathode demonstrates high initial specific capacity(1505 mA h g-1 at 0.1 C) and excellent cycling stability at 1 C over 300 cycles, giving rise to a capacity retention of 91.7% and an average capacity decline of 0.03%cycle-1.展开更多
A robust three-dimensional(3D)interconnected sulfur host and a polysulfide-proof interlayer are key components in high-performance Li–S batteries.Herein,cellulose-based 3D hierarchical porous carbon(HPC)and two-dimen...A robust three-dimensional(3D)interconnected sulfur host and a polysulfide-proof interlayer are key components in high-performance Li–S batteries.Herein,cellulose-based 3D hierarchical porous carbon(HPC)and two-dimensional(2D)lamellar porous carbon(LPC)are employed as the sulfur host and polysulfide-proof inter-layer,respectively,for a Li–S battery.The 3D HPC displays a cross-linked macroporous structure,which allows high sulfur loading and restriction capability and provides unobstructed electrolyte diffusion channels.With a stackable carbon sheet of 2D LPC that has a large plane view size and is ultrathin and porous,the LPC-coated separator effectively inhibits polysulfides.An optimized combination of the HPC and LPC yields an electrode structure that effectively protects the lithium anode against corrosion by polysulfides,giving the cell a high ca-pacity of 1339.4 mAh g^(-1) and high stability,with a capacity decay rate of 0.021% per cycle at 0.2C.This work provides a new understanding of biomaterials and offers a novel strategy to improve the performance of Li–S batteries for practical applications.展开更多
Restraining the shuttle effects of lithium polysulfides is the key to improve the cycling reversibility and stability of lithium-sulfur(Li-S)batteries for which design of robust sulfur hosts has been regarded as the m...Restraining the shuttle effects of lithium polysulfides is the key to improve the cycling reversibility and stability of lithium-sulfur(Li-S)batteries for which design of robust sulfur hosts has been regarded as the most effective strategy.In this work,we report a new type of hybrid sulfur host which is composed of Al_(2)O_(3) homogenously decorated in nitrogen-rich mesoporous carbon framework(NMC-Al_(2)O_(3)).The NMC-Al_(2)O_(3) hybrid host features a poly-dispersed spherical morphology and a mesoporous configuration with high surface area and large pore volume that can accommodate a high sulfur content up to 73.5 wt.%.As a result,the fabricated NMC-Al_(2)O_(3)-S cathode exhibits all-round improvements in electrochemical properties in term of capacities(1,212 mAh·g^(-1)at 0.2 C;755 mAh·g^(-1)at 2 C),cycling charge-discharge reversibility(sustainably 100%efficiencies)and stability(1,000 cycles with only 0.023%capacity decay per cycle at 0.5 C).By contrast,the Al_(2)O_(3)-free NMC-S cathode shows both decreased capacities and rapidly descending Coulombic efficiencies during cycling.Density functional theory(DFH")calculations further reveal that the implanted Al_(2)O_(3) can greatly enhance the chemical adsorption and catalytic conversion for various lithium polysulfides and thereby effectively prevent the polysulfide shuttling and significantly improve the utilizability,reversibility and stability of sulfur cathode.展开更多
Lithium-sulfur batteries(LiSBs)are widely deemed as the most promising energy storage devices to substitute for traditional Li-ion batteries.However,its wide application is impeded by the soluble lithium polysulfides(...Lithium-sulfur batteries(LiSBs)are widely deemed as the most promising energy storage devices to substitute for traditional Li-ion batteries.However,its wide application is impeded by the soluble lithium polysulfides(LiPSs),which is called the shuttle effect,and the irregular distribution of final product Li_(2)S.Herein,based on the interfaces engineering,CoO-Co_(4)N hetero-nanocages are used as the sulfur host for LiSBs.Taking advantage of the polarity of CoO with the conductivity of Co_(4)N,CoO-Co_(4)N nanocages not only can provide large void space for sulfur volume fluctuation,but also can adsorb polysulfides and simultaneously regulate the nucleation of solid Li_(2)S by the‘trapping-diffusion-conversion’mechanism,which significantly enhances the redox kinetic of LiSBs and the utilization of active materials.Eventually,LiSBs with CoO-Co_(4)N nanocages host exhibit higher rate capacity(737 mAh·g^(-1) at 2 C)and cycling stability(662 mAh·g^(-1) at^(-1) C after 350 cycles).Even when the areal sulfur loading is as high as 3.0 mg cm^(-2),a high capacity of 713 mAh·g^(-1) can still be achieved after 100 cycles at 0.2 C.This host with sufficient polar-conductive interfaces expands‘trapping-diffusion-conversion’concept for the design of fast kinetic and high performance LSBs.展开更多
With the high theoretical specific capacity and energy density,lithium-sulfur batteries(LSBs)have been intensively studied as promising candidates for energy storage devices.However,LSBs are largely hindered by inferi...With the high theoretical specific capacity and energy density,lithium-sulfur batteries(LSBs)have been intensively studied as promising candidates for energy storage devices.However,LSBs are largely hindered by inferior sulfur utilization and uncontrollable dendritic growth.Herein,a hierarchical functionalization strategy of stepwise catalytic-adsorption-conversion for sulfur species via the synergetic of the efficiently catalytic host cathode and light multifunctional interlayer has been proposed to concurrently address the issues arising on the dual sides of the LSBs.The multi-layer SnS_(2) micro-flowers embedded into the natural three-dimensional(3D)interconnected carbonized bacterial cellulose(CBC)nanofibers are fabricated as the sulfur host that provides numerous catalytic sites for the rapid catalytic conversion of sulfur species.Moreover,the distinctive CBC-based SnO_(2)-SnS_(2) heterostructure network accompanied high conductive carbon nanofibers as the multifunctional interlayer promotes the rapid anchoringdiffusion-conversion of lithium polysulfides,Li^(+)flux redistribution,and uniform Li deposition.LSBs equipped with our strategy exhibit a high reversible capacity of 1361.5 m A h g^(-1)at 0.2 C and superior cycling stability with an ultra-low capacity fading of 0.031%per cycle in 1000 cycles at 1.5 C and 0.046%at 3 C.A favorable specific capacity of 859.5 m A h g^(-1)at 0.3 C is achieved with a high sulfur mass loading of 5.2 mg cm^(-2),highlighting the potential of practical application.The rational design in this work can provide a feasible solution for high-performance LSBs and promote the development of advanced energy storage devices.展开更多
Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material ...Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material has been used as the host material in Li–S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading(60%) in Li–S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability(up to 500 ℃).In the electrochemical experiment, the performance of the composite cathode with acetylene black(AB) and super-P(S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g,the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li–S battery.展开更多
To anchor the polysulfide and enhance the conversion kinetics of polysulfide to disulfide/sulfide is critical for improving the performance of lithium-sulfur battery.For this purpose,the graphene-supported tin(Ⅳ) pho...To anchor the polysulfide and enhance the conversion kinetics of polysulfide to disulfide/sulfide is critical for improving the performance of lithium-sulfur battery.For this purpose,the graphene-supported tin(Ⅳ) phosphate(Sn(HPO_4)_2·H_2 O,SnP) composites(SnP-G) are employed as the novel sulfur hosts in this work.When compared to the graphene-sulfur and carbon-sulfur composites,the SnP-G-sulfur composites exhibit much better cycling performance at 1.0 C over 800 cycles.Meanwhile,the pouch cell fabricated with the SnP-G-sulfur cathodes also exhibits excellent performance with an initial capacity of1266.6 mAh g^(-1)(S) and capacity retention of 76.9% after 100 cycles at 0.1 C.The adsorption tests,density functional theory(DFT) calculations in combination with physical cha racterizations and electrochemical measurements provide insights into the mechanism of capture-accelerated conversion mechanism of polysulfide at the surface of SnP.DFT calculations indicate that the Li-O bond formed between Li atom(from Li_2 S_n,n=1,2,4,6,8) and O atom(from PO_3-OH in SnP) is the main reason for the strong interactions between Li_2 S_n and SnP.As a result,SnP can effectively restrain the shuttle effect and improving the cycling performance of Li-S cell.In addition,by employing the climbing-image nudged elastic band(ciNEB) methods,the energy barrier for lithium sulfide decomposition(charging reaction) on SnP is proved to decrease significantly compared to that on graphene.It can be concluded that SnP is an effective sulfur hosts acting as dual-functional accelerators for the conversion reactions of polysulfude to sulfide(discharging reaction) as well as polysulfide to sulfur(charging reaction).展开更多
Lithium-sulfur batteries(Li–S batteries) are promising candidates for the next generation high-energy rechargeable Li batteries due to their high theoretical specific capacity(1672 m Ahg-1) and energy density(2500 Wh...Lithium-sulfur batteries(Li–S batteries) are promising candidates for the next generation high-energy rechargeable Li batteries due to their high theoretical specific capacity(1672 m Ahg-1) and energy density(2500 Wh kg-1). The commercialization of Li–S batteries is impeded by several key challenges at cathode side, e.g. the insulating nature of sulfur and discharged products(Li2S 2 and Li2S), the solubility of long-chain polysulfides and volume variation of sulfur cathode upon cycling. Recently, the carbonbased derivatives from metal-organic frameworks(MOFs) has emerged talent in their utilization as cathode hosts for Li–S batteries. They are not only highly conductive and porous to enable the acceleration of Li +/e-transfer and accommodation of volumetric expansion of sulfur cathode during cycling, but also enriched by controllable chemical active sites to enable the adsorption of polysulfides and promotion of their conversion reaction kinetics. In this review, based on the types of MOFs(e.g. ZIF-8, ZIF-67, Prussian blue, Al-MOF, MOF-5, Cu-MOF, Ni-MOF), the synthetic methods, formation process and morphology, structural superiority of MOFs-derived carbon frameworks along with their electrochemical performance as cathode host in Li–S batteries are summarized and discussed.展开更多
A type of carbonate-hosted lead–zinc(Pb–Zn)ore deposits, known as Mississippi Valley Type(MVT)deposits, constitutes an important category of lead–zinc ore deposits. Previous studies proposed a fluid-mixing model to...A type of carbonate-hosted lead–zinc(Pb–Zn)ore deposits, known as Mississippi Valley Type(MVT)deposits, constitutes an important category of lead–zinc ore deposits. Previous studies proposed a fluid-mixing model to account for metal precipitation mechanism of the MVT ore deposits, in which fluids with metal-chloride complexes happen to mix with fluids with reduced sulfur, producing metal sulfide deposition. In this hypothesis, however, the detailed chemical kinetic process of mixing reactions, and especially the controlling factors on the metal precipitation are not yet clearly stated. In this paper, a series of mixing experiments under ambient temperature and pressure conditions were conducted to simulate the fluid mixing process, by titrating the metal-chloride solutions, doping withor without dolomite, and using NaHS solution. Experimental results, combined with the thermodynamic calculations, suggest that H_2S, rather than HS^-or S^(2-),dominated the reactions of Pb and/or Zn precipitation during the fluid mixing process, in which metal precipitation was influenced by the stability of metal complexes and the pH. Given the constant concentrations of metal and total S in fluids, the pH was a primary factor controlling the Pb and/or Zn metal precipitation. This is because neutralizing or neutralized processes for the ore-forming fluids can cause instabilities of Pb and/or Zn chloride complexes and re-distribution of sulfur species, and thus can facilitate the hydrolysis of Pb and Zn ions and precipitation of sulfides. Therefore, a weakly acidic to neutral fluid environment is most favorable for the precipitation of Pb and Zn sulfides associated with the carbonate-hosted Pb–Zn deposits.展开更多
Lithium-sulfur(Li-S)batteries,known for their high energy density,are attracting extensive research interest as a promising next-generation energy storage technology.However,their widespread use has been hampered by c...Lithium-sulfur(Li-S)batteries,known for their high energy density,are attracting extensive research interest as a promising next-generation energy storage technology.However,their widespread use has been hampered by certain issues,including the dissolution and migration of polysulfides,along with sluggish redox kinetics.Metal sulfides present a promising solution to these obstacles regarding their high electrical conductivity,strong chemical adsorption with polysulfides,and remarkable electrocatalytic capabilities for polysulfide conversion.In this review,the recent progress on the utilization of metal sulfide for suppressing polysulfide shuttling in Li-S batteries is systematically summarized,with a special focus on sulfur hosts and functional separators.The critical roles of metal sulfides in realizing high-performing Li-S batteries have been comprehensively discussed by correlating the materials’structure and electrochemical performances.Moreover,the remaining issues/challenges and future perspectives are highlighted.By offering a detailed understanding of the crucial roles of metal sulfides,this review dedicates to contributing valuable knowledge for the pursuit of high-efficiency Li-S batteries based on metal sulfides.展开更多
MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still chal...MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still challenges in modifying the surface functional groups of MXene to further improve the electrochemical performance and increase the structure variety for MXene-based sulfur host.Herein,we report an efficient and flexible nucleophilic substitution(S_(N))strategy to modify the Ti_(3)C_(2)T_(x) surface terminations and purposefully designed Magnolol-modified Ti_(3)C_(2)T_(x)(M-Ti_(3)C_(2)T_(x))as powerful cathode host materials.Benefiting from more C-Ti-O bonds forming and diallyl groups terminations reducing after the dehalogenation and nucleophilic addition reactions,the given M-Ti_(3)C_(2)T_(x) electrode could effectively suppress the lithium polysulfides shuttling via chemisorption and C—S covalent bond formation.Besides,the Magnolol-modified Ti_(3)C_(2)T_(x) significantly accelerates polysulfide redox reaction and reduces the activation energy of Li_(2) S decomposition.As a result,the as-prepared M-Ti_(3)C_(2)T_(x) electrode displays an excellent rate capability and a high reversible capacity of 7.68 mAh cm^(-2)even under 7.2 mg cm^(-2)S-loaded with a low decay rate of 0.07%(from 2 nd cycle).This flexible surface-modified strategy for MXene terminations is expected to be extended to other diverse MXene applications.展开更多
基金supported by the National Natural Science Foundation of China(21805105,21975091 and 21773078)。
文摘Lithium-sulfur batteries(LSBs)are one of the most promising energy storage devices because of their high theoretical energy density;however,inherent issues including poor electrical conductivity and severe dissolution of S and its discharged products hinder their practical applications.MXenes have metallic conductivity,ultra-thin two-dimensional(2D)structures,rich surface functional groups,and macrostructural adjustability and have been widely used to design advanced sulfur hosts.3D network structures assembled by 2D MXene nanosheets have shown superior performance for improving reaction kinetics,accommodating and dispersing sulfur at the micro-/nanoscale,and capturing polysulfides due to their porous interconnected structure.Herein,the applications of MXene architectures related to 2D layered structures,3D multilayered structures,and 3D spherical structures as sulfur hosts are reviewed.The structure-performance relationship,challenges for current designs,and opportunities for future 3D architectures for LSBs are also analyzed.
基金the Guangdong Provincial Natural Science Foundation(nos.2017A030313283,2017A030313083)National Natural Science Foundation of China(NSFC,no.51602109)。
文摘The sluggish redox kinetics and shuttle effect of soluble polysulfides intermediate primarily restrict the electrochemical performance of lithium–sulfur(Li–S) batteries. To address this issue, rational design of high–efficiency sulfur host is increasingly demanded to accelerate the polysulfides conversion during charge/discharge process. Herein, we propose a macro–mesoporous sulfur host(Co@NC), which comprises highly dispersed cobalt nanoparticles embedding in N–doped ultrathin carbon nanosheets. Co@NC is simply synthesized via a carbon nitride–derived pyrolysis approach. Owing to the highly conductive graphene–like matrix and well defined porous structure, the designed multifunctional Co@NC host enables rapid electron/ion transport, electrolyte penetration and effective sulfur trapping. More significantly,N heteroatoms and homogeneous Co nanocatalysts in the graphitic carbon nanosheets could serve as chemisorption sites as well as electrocatalytic centers for sulfur species. These Co–N active sites can synergistically facilitate the redox conversion kinetics and mitigate the shuttling of polysulfides, thus leading to improved electrochemical cycling performance of Li–S batteries. As a consequence, the S/Co@NC cathode demonstrates high initial specific capacity(1505 mA h g-1 at 0.1 C) and excellent cycling stability at 1 C over 300 cycles, giving rise to a capacity retention of 91.7% and an average capacity decline of 0.03%cycle-1.
基金The authors gratefully acknowledge the financial support by the Joint Funds of the Natural Science Basic Research Project of Shaanxi Province(2021JLM-23)University Joint Project of Shaanxi Province(2021GXLH-Z-067)+3 种基金Anhui Provincial Natural Science Foundation for Outstanding Young Scholar(2208085Y05)Anhui Provincial Scientific Reuter Foundation for Returned Scholars(2022LCX030)the National Natural Science Foundation of China(51801144)Guangxi Key Labo-ratory of Low Carbon Energy Material(2021GXKLLCEM04)。
文摘A robust three-dimensional(3D)interconnected sulfur host and a polysulfide-proof interlayer are key components in high-performance Li–S batteries.Herein,cellulose-based 3D hierarchical porous carbon(HPC)and two-dimensional(2D)lamellar porous carbon(LPC)are employed as the sulfur host and polysulfide-proof inter-layer,respectively,for a Li–S battery.The 3D HPC displays a cross-linked macroporous structure,which allows high sulfur loading and restriction capability and provides unobstructed electrolyte diffusion channels.With a stackable carbon sheet of 2D LPC that has a large plane view size and is ultrathin and porous,the LPC-coated separator effectively inhibits polysulfides.An optimized combination of the HPC and LPC yields an electrode structure that effectively protects the lithium anode against corrosion by polysulfides,giving the cell a high ca-pacity of 1339.4 mAh g^(-1) and high stability,with a capacity decay rate of 0.021% per cycle at 0.2C.This work provides a new understanding of biomaterials and offers a novel strategy to improve the performance of Li–S batteries for practical applications.
基金the Open Project of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University(No.2018-13K)and the Fundamental Research Funds for the Central Universities.
文摘Restraining the shuttle effects of lithium polysulfides is the key to improve the cycling reversibility and stability of lithium-sulfur(Li-S)batteries for which design of robust sulfur hosts has been regarded as the most effective strategy.In this work,we report a new type of hybrid sulfur host which is composed of Al_(2)O_(3) homogenously decorated in nitrogen-rich mesoporous carbon framework(NMC-Al_(2)O_(3)).The NMC-Al_(2)O_(3) hybrid host features a poly-dispersed spherical morphology and a mesoporous configuration with high surface area and large pore volume that can accommodate a high sulfur content up to 73.5 wt.%.As a result,the fabricated NMC-Al_(2)O_(3)-S cathode exhibits all-round improvements in electrochemical properties in term of capacities(1,212 mAh·g^(-1)at 0.2 C;755 mAh·g^(-1)at 2 C),cycling charge-discharge reversibility(sustainably 100%efficiencies)and stability(1,000 cycles with only 0.023%capacity decay per cycle at 0.5 C).By contrast,the Al_(2)O_(3)-free NMC-S cathode shows both decreased capacities and rapidly descending Coulombic efficiencies during cycling.Density functional theory(DFH")calculations further reveal that the implanted Al_(2)O_(3) can greatly enhance the chemical adsorption and catalytic conversion for various lithium polysulfides and thereby effectively prevent the polysulfide shuttling and significantly improve the utilizability,reversibility and stability of sulfur cathode.
基金This work was supported by Shenzhen Basic Research Project(JCYJ20190813172807127).
文摘Lithium-sulfur batteries(LiSBs)are widely deemed as the most promising energy storage devices to substitute for traditional Li-ion batteries.However,its wide application is impeded by the soluble lithium polysulfides(LiPSs),which is called the shuttle effect,and the irregular distribution of final product Li_(2)S.Herein,based on the interfaces engineering,CoO-Co_(4)N hetero-nanocages are used as the sulfur host for LiSBs.Taking advantage of the polarity of CoO with the conductivity of Co_(4)N,CoO-Co_(4)N nanocages not only can provide large void space for sulfur volume fluctuation,but also can adsorb polysulfides and simultaneously regulate the nucleation of solid Li_(2)S by the‘trapping-diffusion-conversion’mechanism,which significantly enhances the redox kinetic of LiSBs and the utilization of active materials.Eventually,LiSBs with CoO-Co_(4)N nanocages host exhibit higher rate capacity(737 mAh·g^(-1) at 2 C)and cycling stability(662 mAh·g^(-1) at^(-1) C after 350 cycles).Even when the areal sulfur loading is as high as 3.0 mg cm^(-2),a high capacity of 713 mAh·g^(-1) can still be achieved after 100 cycles at 0.2 C.This host with sufficient polar-conductive interfaces expands‘trapping-diffusion-conversion’concept for the design of fast kinetic and high performance LSBs.
基金financially supported by the National Natural Science Foundation of China (52073212,52272303)。
文摘With the high theoretical specific capacity and energy density,lithium-sulfur batteries(LSBs)have been intensively studied as promising candidates for energy storage devices.However,LSBs are largely hindered by inferior sulfur utilization and uncontrollable dendritic growth.Herein,a hierarchical functionalization strategy of stepwise catalytic-adsorption-conversion for sulfur species via the synergetic of the efficiently catalytic host cathode and light multifunctional interlayer has been proposed to concurrently address the issues arising on the dual sides of the LSBs.The multi-layer SnS_(2) micro-flowers embedded into the natural three-dimensional(3D)interconnected carbonized bacterial cellulose(CBC)nanofibers are fabricated as the sulfur host that provides numerous catalytic sites for the rapid catalytic conversion of sulfur species.Moreover,the distinctive CBC-based SnO_(2)-SnS_(2) heterostructure network accompanied high conductive carbon nanofibers as the multifunctional interlayer promotes the rapid anchoringdiffusion-conversion of lithium polysulfides,Li^(+)flux redistribution,and uniform Li deposition.LSBs equipped with our strategy exhibit a high reversible capacity of 1361.5 m A h g^(-1)at 0.2 C and superior cycling stability with an ultra-low capacity fading of 0.031%per cycle in 1000 cycles at 1.5 C and 0.046%at 3 C.A favorable specific capacity of 859.5 m A h g^(-1)at 0.3 C is achieved with a high sulfur mass loading of 5.2 mg cm^(-2),highlighting the potential of practical application.The rational design in this work can provide a feasible solution for high-performance LSBs and promote the development of advanced energy storage devices.
基金Thanks for the financial support from the National Nature Science Foundation of China (No. 21471091), Academy of Sciences large apparatus United Fund (No. 11179043), the Fundamental Research Funds of Shandong University (No. 2015JC007), and the Taishan Scholar Project of Shandong Province (No. ts201511004).
基金financial aid from the National Natural Science Foundation of Guangdong Province (Grant No. 2016A030310435)Youth Scholars Fundation of South China Normal University (Grant No. 15KJ01)
文摘Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material has been used as the host material in Li–S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading(60%) in Li–S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability(up to 500 ℃).In the electrochemical experiment, the performance of the composite cathode with acetylene black(AB) and super-P(S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g,the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li–S battery.
基金supported by the funding from the Strategy Priority Research Program of Chinese Academy of Science (Grant No. XDA17020404)the DICP&QIBEBT (DICP&QIBEBT UN201702)+2 种基金the R&D Projects in Key Areas of Guangdong Province (2019B090908001)Science and Technology Innovation Foundation of Dalian (2018J11CY020)the Defense Industrial Technology Development Program (JCKY2018130C107)。
文摘To anchor the polysulfide and enhance the conversion kinetics of polysulfide to disulfide/sulfide is critical for improving the performance of lithium-sulfur battery.For this purpose,the graphene-supported tin(Ⅳ) phosphate(Sn(HPO_4)_2·H_2 O,SnP) composites(SnP-G) are employed as the novel sulfur hosts in this work.When compared to the graphene-sulfur and carbon-sulfur composites,the SnP-G-sulfur composites exhibit much better cycling performance at 1.0 C over 800 cycles.Meanwhile,the pouch cell fabricated with the SnP-G-sulfur cathodes also exhibits excellent performance with an initial capacity of1266.6 mAh g^(-1)(S) and capacity retention of 76.9% after 100 cycles at 0.1 C.The adsorption tests,density functional theory(DFT) calculations in combination with physical cha racterizations and electrochemical measurements provide insights into the mechanism of capture-accelerated conversion mechanism of polysulfide at the surface of SnP.DFT calculations indicate that the Li-O bond formed between Li atom(from Li_2 S_n,n=1,2,4,6,8) and O atom(from PO_3-OH in SnP) is the main reason for the strong interactions between Li_2 S_n and SnP.As a result,SnP can effectively restrain the shuttle effect and improving the cycling performance of Li-S cell.In addition,by employing the climbing-image nudged elastic band(ciNEB) methods,the energy barrier for lithium sulfide decomposition(charging reaction) on SnP is proved to decrease significantly compared to that on graphene.It can be concluded that SnP is an effective sulfur hosts acting as dual-functional accelerators for the conversion reactions of polysulfude to sulfide(discharging reaction) as well as polysulfide to sulfur(charging reaction).
基金supported by National Key R&D Program of China(2016YFB0901600)the National Natural Science Foundation of China(51772313 , U1830113 and 51802334)
文摘Lithium-sulfur batteries(Li–S batteries) are promising candidates for the next generation high-energy rechargeable Li batteries due to their high theoretical specific capacity(1672 m Ahg-1) and energy density(2500 Wh kg-1). The commercialization of Li–S batteries is impeded by several key challenges at cathode side, e.g. the insulating nature of sulfur and discharged products(Li2S 2 and Li2S), the solubility of long-chain polysulfides and volume variation of sulfur cathode upon cycling. Recently, the carbonbased derivatives from metal-organic frameworks(MOFs) has emerged talent in their utilization as cathode hosts for Li–S batteries. They are not only highly conductive and porous to enable the acceleration of Li +/e-transfer and accommodation of volumetric expansion of sulfur cathode during cycling, but also enriched by controllable chemical active sites to enable the adsorption of polysulfides and promotion of their conversion reaction kinetics. In this review, based on the types of MOFs(e.g. ZIF-8, ZIF-67, Prussian blue, Al-MOF, MOF-5, Cu-MOF, Ni-MOF), the synthetic methods, formation process and morphology, structural superiority of MOFs-derived carbon frameworks along with their electrochemical performance as cathode host in Li–S batteries are summarized and discussed.
基金supported jointly by the National Key R&D Program of China (No. 2016YFC0600408)the National Natural Science Foundation of China (Nos. 41572060, 41773054, U1133602, 41802089)+3 种基金China Postdoctoral Science Foundation (No. 2017M610614)projects of YM Lab (2011)Innovation Team of Yunnan Province and KMUST (2008 and 2012)Yunnan and Kunming University of Science and Technology Postdoctoral Sustentation Fund
文摘A type of carbonate-hosted lead–zinc(Pb–Zn)ore deposits, known as Mississippi Valley Type(MVT)deposits, constitutes an important category of lead–zinc ore deposits. Previous studies proposed a fluid-mixing model to account for metal precipitation mechanism of the MVT ore deposits, in which fluids with metal-chloride complexes happen to mix with fluids with reduced sulfur, producing metal sulfide deposition. In this hypothesis, however, the detailed chemical kinetic process of mixing reactions, and especially the controlling factors on the metal precipitation are not yet clearly stated. In this paper, a series of mixing experiments under ambient temperature and pressure conditions were conducted to simulate the fluid mixing process, by titrating the metal-chloride solutions, doping withor without dolomite, and using NaHS solution. Experimental results, combined with the thermodynamic calculations, suggest that H_2S, rather than HS^-or S^(2-),dominated the reactions of Pb and/or Zn precipitation during the fluid mixing process, in which metal precipitation was influenced by the stability of metal complexes and the pH. Given the constant concentrations of metal and total S in fluids, the pH was a primary factor controlling the Pb and/or Zn metal precipitation. This is because neutralizing or neutralized processes for the ore-forming fluids can cause instabilities of Pb and/or Zn chloride complexes and re-distribution of sulfur species, and thus can facilitate the hydrolysis of Pb and Zn ions and precipitation of sulfides. Therefore, a weakly acidic to neutral fluid environment is most favorable for the precipitation of Pb and Zn sulfides associated with the carbonate-hosted Pb–Zn deposits.
基金supported by the open research fund of the State Key Laboratory of Organic Electronics and Information Displays,the Startup Foundation for Introducing Talent of NUIST(Nos.2021r090 and 2021r091)Jiangsu Provincial Scientific Research and Practice Innovation Program(Nos.SJCX23_0420 and SJCX23_0421).
文摘Lithium-sulfur(Li-S)batteries,known for their high energy density,are attracting extensive research interest as a promising next-generation energy storage technology.However,their widespread use has been hampered by certain issues,including the dissolution and migration of polysulfides,along with sluggish redox kinetics.Metal sulfides present a promising solution to these obstacles regarding their high electrical conductivity,strong chemical adsorption with polysulfides,and remarkable electrocatalytic capabilities for polysulfide conversion.In this review,the recent progress on the utilization of metal sulfide for suppressing polysulfide shuttling in Li-S batteries is systematically summarized,with a special focus on sulfur hosts and functional separators.The critical roles of metal sulfides in realizing high-performing Li-S batteries have been comprehensively discussed by correlating the materials’structure and electrochemical performances.Moreover,the remaining issues/challenges and future perspectives are highlighted.By offering a detailed understanding of the crucial roles of metal sulfides,this review dedicates to contributing valuable knowledge for the pursuit of high-efficiency Li-S batteries based on metal sulfides.
基金jointly supported by the National Natural Science Foundation of China(52202286,51971124,52171217)Zhejiang Provincial Natural Science Foundation of China(LZ21E010001)。
基金the support from CNPC Innovation Found(2021DQ02-1001)Liao Ning Revitalization Talents Program(XLYC1907144)Xinghai Talent Cultivation Plan(X20200303)。
文摘MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still challenges in modifying the surface functional groups of MXene to further improve the electrochemical performance and increase the structure variety for MXene-based sulfur host.Herein,we report an efficient and flexible nucleophilic substitution(S_(N))strategy to modify the Ti_(3)C_(2)T_(x) surface terminations and purposefully designed Magnolol-modified Ti_(3)C_(2)T_(x)(M-Ti_(3)C_(2)T_(x))as powerful cathode host materials.Benefiting from more C-Ti-O bonds forming and diallyl groups terminations reducing after the dehalogenation and nucleophilic addition reactions,the given M-Ti_(3)C_(2)T_(x) electrode could effectively suppress the lithium polysulfides shuttling via chemisorption and C—S covalent bond formation.Besides,the Magnolol-modified Ti_(3)C_(2)T_(x) significantly accelerates polysulfide redox reaction and reduces the activation energy of Li_(2) S decomposition.As a result,the as-prepared M-Ti_(3)C_(2)T_(x) electrode displays an excellent rate capability and a high reversible capacity of 7.68 mAh cm^(-2)even under 7.2 mg cm^(-2)S-loaded with a low decay rate of 0.07%(from 2 nd cycle).This flexible surface-modified strategy for MXene terminations is expected to be extended to other diverse MXene applications.