Lithium-sulfur batteries(LSBs)are promising energy storage systems due to their low cost and high energy density.However,sluggish reaction kinetics and the“shuttle effect”of lithium polysulfides(LiPSs)from sulfur ca...Lithium-sulfur batteries(LSBs)are promising energy storage systems due to their low cost and high energy density.However,sluggish reaction kinetics and the“shuttle effect”of lithium polysulfides(LiPSs)from sulfur cathode hinder the practical application of LSBs.In this work,a separator loaded with the Eu_(2)O_(3-δ)nanoparticles/carbon nanotube interlayer is designed to immobilize Li PSs and catalyze their conversion reaction.The oxygen-deficient Eu_(2)O_(3-δ)nanoparticles,with abundant catalytic sites,promote Li PSs conversion kinetics even at high current densities.Moreover,the unique 4f electronic structure of Eu_(2)O_(3-δ)effectively mitigates undesired sulfur cathode crossover,significantly enhancing the cycling performance of LSBs.Specifically,a high capacity of 620.7 mAh/g at a rate of 5 C is achieved,maintaining at 545 mAh/g after 300 cycles at 1 C.This work demonstrates the potential application of rare earth catalysts in LSBs,offering new research avenues for promoting dynamic conversion design in electrocatalysts.展开更多
Lewis acid molten salt etching of MAX phases has emerged as a universal route to synthesize fluorinefree MXenes.However,the layer-stacked structure and halogen-rich termination of such MXenes limit their widespread us...Lewis acid molten salt etching of MAX phases has emerged as a universal route to synthesize fluorinefree MXenes.However,the layer-stacked structure and halogen-rich termination of such MXenes limit their widespread use in energy storage.Herein,a sequential ion intercalation strategy is proposed to modulate the interlayer structure of the molten salt-etched Ti_(3)C_(2)T_(x) MXene(MS-MXene)for improving its lithium storage performance.The sequential ion intercalation process involved immersing MS-MXene in mixed alkaline solutions of LiOH,NaOH,and KOH,allowing for the pre-intercalation of smaller Li^(+)ions,which then facilitated the subsequent intercalation of larger Na^(+)and K^(+)ions(Li/Na/K-MXene).Consequently,the interlayer spacing of MS-MXene experienced an expansion from 11.02Å to 11.22Å,endowing the Li/Na/K-MXene with abundant surface active sites and improved ion/electron transport capabilities.When configured as an anode for LIBs,the Li/Na/K-MXene exhibited a high capacity of 323.1 mA h g^(-1) at 50 mA g^(-1),a superior rate capability of 170.0 mA h g^(-1) at 2000 mA g^(-1),and robust cycling stability with no decay over 1200 cycles.The proposed approach shows promise for expanding to additional classes of MXenes and can potentially advance MS-MXene for practical energy storage applications.展开更多
The lamellar precursor of the FER type zeolite(PREFER)was applied to develop the interlayer expanded zeolite IEZ(interlayer-expanded zeolite)-FER(D4h)with extra-large pores through hydrothermal acid treatment-assisted...The lamellar precursor of the FER type zeolite(PREFER)was applied to develop the interlayer expanded zeolite IEZ(interlayer-expanded zeolite)-FER(D4h)with extra-large pores through hydrothermal acid treatment-assisted molecular alkoxysilylation,using 1,3,5,7-tetramethyl cyclotetrasiloxane(D4h)as a silylating agent to interconnect neighboring zeolitic layers.The interlayer expanded structure was well preserved after calcination at 823 K,yielding a hydrophilic material denoted as IEZ-FER(D4h-B).The as-made IEZ-FER(D4h)exhibits expanded interlayer spacing along the a-axis.The 4-membered rings(4MR)exist in IEZ-FER(D4h)as the secondary structure building units,while the methyl groups therein attached result in the hydrophobic properties.The newly formed channel systems are composed of intersecting 14MR and 12MR pores along the[001]and[010]directions,respectively,which are larger than those of the conventional 3D FER.The powder XRD patterns determine that IEZ-FER(D4h)has a crystalline structure with the IMM2 space group and unit cell parameters of a=28.0285(39)A,b=14.0921(6)A,c=7.4395(3)A.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.52104312,22278329,22271229,22105153)Qin Chuangyuan Talent Project of Shaanxi Province(Nos.2021QCYRC4-43,QCYRCXM-2022-308)the State Key Laboratory for Electrical Insulation and Power Equipment(No.EIPE23125)。
文摘Lithium-sulfur batteries(LSBs)are promising energy storage systems due to their low cost and high energy density.However,sluggish reaction kinetics and the“shuttle effect”of lithium polysulfides(LiPSs)from sulfur cathode hinder the practical application of LSBs.In this work,a separator loaded with the Eu_(2)O_(3-δ)nanoparticles/carbon nanotube interlayer is designed to immobilize Li PSs and catalyze their conversion reaction.The oxygen-deficient Eu_(2)O_(3-δ)nanoparticles,with abundant catalytic sites,promote Li PSs conversion kinetics even at high current densities.Moreover,the unique 4f electronic structure of Eu_(2)O_(3-δ)effectively mitigates undesired sulfur cathode crossover,significantly enhancing the cycling performance of LSBs.Specifically,a high capacity of 620.7 mAh/g at a rate of 5 C is achieved,maintaining at 545 mAh/g after 300 cycles at 1 C.This work demonstrates the potential application of rare earth catalysts in LSBs,offering new research avenues for promoting dynamic conversion design in electrocatalysts.
基金financially supported by the National Natural Science Foundation of China(Grant No.U2004212).
文摘Lewis acid molten salt etching of MAX phases has emerged as a universal route to synthesize fluorinefree MXenes.However,the layer-stacked structure and halogen-rich termination of such MXenes limit their widespread use in energy storage.Herein,a sequential ion intercalation strategy is proposed to modulate the interlayer structure of the molten salt-etched Ti_(3)C_(2)T_(x) MXene(MS-MXene)for improving its lithium storage performance.The sequential ion intercalation process involved immersing MS-MXene in mixed alkaline solutions of LiOH,NaOH,and KOH,allowing for the pre-intercalation of smaller Li^(+)ions,which then facilitated the subsequent intercalation of larger Na^(+)and K^(+)ions(Li/Na/K-MXene).Consequently,the interlayer spacing of MS-MXene experienced an expansion from 11.02Å to 11.22Å,endowing the Li/Na/K-MXene with abundant surface active sites and improved ion/electron transport capabilities.When configured as an anode for LIBs,the Li/Na/K-MXene exhibited a high capacity of 323.1 mA h g^(-1) at 50 mA g^(-1),a superior rate capability of 170.0 mA h g^(-1) at 2000 mA g^(-1),and robust cycling stability with no decay over 1200 cycles.The proposed approach shows promise for expanding to additional classes of MXenes and can potentially advance MS-MXene for practical energy storage applications.
基金support from the NSFC of China(grant no.21872052,21972043 and 21972044)the China Ministry of Science and Technology(2016YFA0202804).
文摘The lamellar precursor of the FER type zeolite(PREFER)was applied to develop the interlayer expanded zeolite IEZ(interlayer-expanded zeolite)-FER(D4h)with extra-large pores through hydrothermal acid treatment-assisted molecular alkoxysilylation,using 1,3,5,7-tetramethyl cyclotetrasiloxane(D4h)as a silylating agent to interconnect neighboring zeolitic layers.The interlayer expanded structure was well preserved after calcination at 823 K,yielding a hydrophilic material denoted as IEZ-FER(D4h-B).The as-made IEZ-FER(D4h)exhibits expanded interlayer spacing along the a-axis.The 4-membered rings(4MR)exist in IEZ-FER(D4h)as the secondary structure building units,while the methyl groups therein attached result in the hydrophobic properties.The newly formed channel systems are composed of intersecting 14MR and 12MR pores along the[001]and[010]directions,respectively,which are larger than those of the conventional 3D FER.The powder XRD patterns determine that IEZ-FER(D4h)has a crystalline structure with the IMM2 space group and unit cell parameters of a=28.0285(39)A,b=14.0921(6)A,c=7.4395(3)A.
