TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bul...TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bulk structure,the TiNb_(2)O_(7)electrode still suffers from unsatisfactory lithium storage performance.Herein,we demonstrate a spatially confined strategy toward a novel TiNb_(2)O_(7)-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route,where TiNb_(2)O_(7)quantum dots with a particle size of 2-3 nm are evenly embedded into N-doped mesoporous carbon(NMC)and Ti_(3)C_(2)T_(X)MXene.Impressively,the as-prepared TiNb_(2)O_(7)-NMC/MXene anode exhibits a high reversible capacity(486.2 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles)and long cycle lifespan(363.4 mAh g^(-1)at ss1 A g^(-1)after 500 cycles).Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb_(2)O_(7)quantum dots,2D Ti_(3)C_(2)T_(X)MXene nanosheets,and N-doped mesoporous carbon.The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.展开更多
As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires com...As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.展开更多
MXene is an emerging class of two-dimensional(2D)layered transition metal carbides or nitrides.Due to the highly tunable components and surface functional groups,it holds great potential in electrocatalytic hydrogen e...MXene is an emerging class of two-dimensional(2D)layered transition metal carbides or nitrides.Due to the highly tunable components and surface functional groups,it holds great potential in electrocatalytic hydrogen evolution reaction(HER).However,MXene nanosheet suffers from a strong tendency to restack and a lack of active edge sites.In this work,the porous Ti_(3)C_(2)T_(x)was synthesized by an oxidation and etching two-step strategy and then characterized by a series of spectroscopic techniques.The obtained porous Ti_(3)C_(2)T_(x)possesses a large number of in-plane pores.This not only creates abundant active edge sites but also enhances the mass transfer and increases the accessibility of the active sites.Compared with Ti_(3)C_(2)T_(x),in a 0.5 mol/L H_(2)SO_(4)electrolyte,the porous Ti_(3)C_(2)T_(x)shows a 65.6%higher electrochemical surface area(ECSA)(440 mF/cm^(2)),a 95.2%lower charge transfer resistance(12.8Ω),and a 69.8%lower Tafel slope(144 mV/dec),and thus exhibits lower overpotential with good stability at a current density of 10 mA/cm^(2).At the same time,the HER performance of the porous Ti_(3)C_(2)T_(x)can be further enhanced by near-infrared laser irradiation based on the localized surface plasmon resonance effect.展开更多
基金support from the Natural Science Foundation of Shanghai(23ZR1423800),Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(18SG35)Open Research Fund of Shanghai Key Laboratory of Green Chemistry and Chemical Processes(East China Normal University)Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University.
文摘TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bulk structure,the TiNb_(2)O_(7)electrode still suffers from unsatisfactory lithium storage performance.Herein,we demonstrate a spatially confined strategy toward a novel TiNb_(2)O_(7)-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route,where TiNb_(2)O_(7)quantum dots with a particle size of 2-3 nm are evenly embedded into N-doped mesoporous carbon(NMC)and Ti_(3)C_(2)T_(X)MXene.Impressively,the as-prepared TiNb_(2)O_(7)-NMC/MXene anode exhibits a high reversible capacity(486.2 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles)and long cycle lifespan(363.4 mAh g^(-1)at ss1 A g^(-1)after 500 cycles).Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb_(2)O_(7)quantum dots,2D Ti_(3)C_(2)T_(X)MXene nanosheets,and N-doped mesoporous carbon.The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.
基金support from the National Key Research and Development Program of China(No.2021YFB3701503)the Key Research and Development Program of Ningbo,China(No.2023Z107).
文摘As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.
文摘MXene is an emerging class of two-dimensional(2D)layered transition metal carbides or nitrides.Due to the highly tunable components and surface functional groups,it holds great potential in electrocatalytic hydrogen evolution reaction(HER).However,MXene nanosheet suffers from a strong tendency to restack and a lack of active edge sites.In this work,the porous Ti_(3)C_(2)T_(x)was synthesized by an oxidation and etching two-step strategy and then characterized by a series of spectroscopic techniques.The obtained porous Ti_(3)C_(2)T_(x)possesses a large number of in-plane pores.This not only creates abundant active edge sites but also enhances the mass transfer and increases the accessibility of the active sites.Compared with Ti_(3)C_(2)T_(x),in a 0.5 mol/L H_(2)SO_(4)electrolyte,the porous Ti_(3)C_(2)T_(x)shows a 65.6%higher electrochemical surface area(ECSA)(440 mF/cm^(2)),a 95.2%lower charge transfer resistance(12.8Ω),and a 69.8%lower Tafel slope(144 mV/dec),and thus exhibits lower overpotential with good stability at a current density of 10 mA/cm^(2).At the same time,the HER performance of the porous Ti_(3)C_(2)T_(x)can be further enhanced by near-infrared laser irradiation based on the localized surface plasmon resonance effect.
