Restricted by their energy storage mechanism,current energy storage devices have certain drawbacks,such as low power density for batteries and low energy density for supercapacitors.Fortunately,the nearest ion capacit...Restricted by their energy storage mechanism,current energy storage devices have certain drawbacks,such as low power density for batteries and low energy density for supercapacitors.Fortunately,the nearest ion capacitors,such as lithium-ion and sodium-ion capacitors containing battery-type and capacitor-type electrodes,may allow achieving both high energy and power densities.For the inspiration,a new zinc-ion capacitor(ZIC)has been designed and realized by assembling the free-standing manganese dioxide-carbon nanotubes(MnO2-CNTs)battery-type cathode and MXene(Ti3C2Tx)capacitortype anode in an aqueous electrolyte.The ZIC can avoid the insecurity issues that frequently occurred in lithium-ion and sodium-ion capacitors in organic electrolytes.As expected,the ZIC in an aqueous liquid electrolyte exhibits excellent electrochemical performance(based on the total weight of cathode and anode),such as a high specific capacitance of 115.1 F g?1(1 mV s?1),high energy density of 98.6 Wh kg?1(77.5 W kg?1),high power density of 2480.6 W kg?1(29.7 Wh kg?1),and high capacitance retention of^83.6%of its initial capacitance(15,000 cycles).Even in an aqueous gel electrolyte,the ZIC also exhibits excellent performance.This work provides an essential strategy for designing next-generation high-performance energy storage devices.展开更多
Ti_(3)C_(2)T_(x)MXene shows great potential in the application as microwave absorbers due to its high attenuation ability.However,excessively high permittivity and self-stacking are the main obstacles that constrain i...Ti_(3)C_(2)T_(x)MXene shows great potential in the application as microwave absorbers due to its high attenuation ability.However,excessively high permittivity and self-stacking are the main obstacles that constrain its wide range of applications.To tackle these problems,herein,the microspheres of SiO_(2)@Ti_(3)C_(2)T_(x)@CoNi with the hydrangea-like core-shell structure were designed and prepared by a combinatorial electrostatic assembly and hydrothermal reaction method.These microspheres are constructed by an outside layer of CoNi nanosheets and intermediate Ti_(3)C_(2)T_(x)MXene nanosheets wrapping on the core of modified SiO_(2),engendering both homogenous and heterogeneous interfaces.Such trilayer SiO_(2)@Ti_(3)C_(2)T_(x)@CoNi microspheres are“magnetic microsize supercapacitors”that can not only induce dielectric loss and magnetic loss but also provide multilayer interfaces to enhance the interfacial polarization.The optimized impedance matching and core-shell structure could boost the reflection loss(RL)by electromagnetic synergy.The synthesized SiO_(2)@Ti_(3)C_(2)T_(x)@CoNi microspheres demonstrate outstanding microwave absorption(MA)performance benefited from these advantages.The obtained RL value was-63.95 dB at an ultra-thin thickness of 1.2 mm,corresponding to an effective absorption bandwidth(EAB)of 4.56 GHz.This work demonstrates that the trilayer core-shell structure designing strategy is highly efficient for tuning the MA performance of MXene-based microspheres.展开更多
Cation additives can efficiently enhance the total electrochemical capabilities of zinc-ion hybrid capacitors (ZHCs).However their energy storage mechanisms in zinc-based systems are still under debate.Herein,we modul...Cation additives can efficiently enhance the total electrochemical capabilities of zinc-ion hybrid capacitors (ZHCs).However their energy storage mechanisms in zinc-based systems are still under debate.Herein,we modulate the electrolyte and achieve dual-ion storage by adding magnesium ions.And we assemble several Zn//activated carbon devices with different electrolyte concentrations and investigate their electrochemical reaction dynamic behaviors.The zinc-ion capacitor with Mg^(2+)mixed solution delivers 82 mAh·g^(-1)capacity at 1 A·g^(-1) and maintains 91%of the original capacitance after 10000 cycling.It is superior to the other assembled zinc-ion devices in single-component electrolytes.The finding demonstrates that the double-ion storage mechanism enables the superior rate performance and long cycle lifetime of ZHCs.展开更多
Developing electrochemical energy storage devices with high energy and power densities,long cycling life,as well as low cost is of great significance.Hybrid metal-ion capacitors(MICs),commonly consisting of high energ...Developing electrochemical energy storage devices with high energy and power densities,long cycling life,as well as low cost is of great significance.Hybrid metal-ion capacitors(MICs),commonly consisting of high energy battery-type anodes and high power capacitor-type cathodes,have become a trade-off between batteries and supercapacitors.Tremendous efforts have been devoted to searching for high-performance electrode materials due to poor rate capability of anodes,low capacity of cathodes,and interior sluggish kinetic match.Carbon materials with large surface area,good electrical conductivity and stability have been considered to be ideal candidates for electrodes of MICs.In this review,the advanced carbon materials directly as cathodes and anodes of MICs are systematically summarized.Then,the key structural/chemical factors including the structure engineering,porous characteristics,and heteroatom incorporation for improving electrochemical performance of carbon materials are highlighted.Additionally,the challenges and opportunities for future research on carbon materials in MICs are also proposed.展开更多
基金supported by the Anhui Provincial Natural Science Foundation(1908085QF251)Foundation for the Introduction of High-Level Talents of Anhui University(S020118002/061)+1 种基金National Natural Science Foundation of China(11704002)Support Project of Outstanding Young Talents in Anhui Provincial Universities(gxyqZD2018006).
文摘Restricted by their energy storage mechanism,current energy storage devices have certain drawbacks,such as low power density for batteries and low energy density for supercapacitors.Fortunately,the nearest ion capacitors,such as lithium-ion and sodium-ion capacitors containing battery-type and capacitor-type electrodes,may allow achieving both high energy and power densities.For the inspiration,a new zinc-ion capacitor(ZIC)has been designed and realized by assembling the free-standing manganese dioxide-carbon nanotubes(MnO2-CNTs)battery-type cathode and MXene(Ti3C2Tx)capacitortype anode in an aqueous electrolyte.The ZIC can avoid the insecurity issues that frequently occurred in lithium-ion and sodium-ion capacitors in organic electrolytes.As expected,the ZIC in an aqueous liquid electrolyte exhibits excellent electrochemical performance(based on the total weight of cathode and anode),such as a high specific capacitance of 115.1 F g?1(1 mV s?1),high energy density of 98.6 Wh kg?1(77.5 W kg?1),high power density of 2480.6 W kg?1(29.7 Wh kg?1),and high capacitance retention of^83.6%of its initial capacitance(15,000 cycles).Even in an aqueous gel electrolyte,the ZIC also exhibits excellent performance.This work provides an essential strategy for designing next-generation high-performance energy storage devices.
基金supported by the National Natural Science Foundation of China(U2004177)the Outstanding Youth Fund of Henan Province(212300410081)the Support Plan for Scientific and Technological Innovation Talents in Colleges and Universities of Henan Province(22HASTIT001)。
文摘Ti_(3)C_(2)T_(x)MXene shows great potential in the application as microwave absorbers due to its high attenuation ability.However,excessively high permittivity and self-stacking are the main obstacles that constrain its wide range of applications.To tackle these problems,herein,the microspheres of SiO_(2)@Ti_(3)C_(2)T_(x)@CoNi with the hydrangea-like core-shell structure were designed and prepared by a combinatorial electrostatic assembly and hydrothermal reaction method.These microspheres are constructed by an outside layer of CoNi nanosheets and intermediate Ti_(3)C_(2)T_(x)MXene nanosheets wrapping on the core of modified SiO_(2),engendering both homogenous and heterogeneous interfaces.Such trilayer SiO_(2)@Ti_(3)C_(2)T_(x)@CoNi microspheres are“magnetic microsize supercapacitors”that can not only induce dielectric loss and magnetic loss but also provide multilayer interfaces to enhance the interfacial polarization.The optimized impedance matching and core-shell structure could boost the reflection loss(RL)by electromagnetic synergy.The synthesized SiO_(2)@Ti_(3)C_(2)T_(x)@CoNi microspheres demonstrate outstanding microwave absorption(MA)performance benefited from these advantages.The obtained RL value was-63.95 dB at an ultra-thin thickness of 1.2 mm,corresponding to an effective absorption bandwidth(EAB)of 4.56 GHz.This work demonstrates that the trilayer core-shell structure designing strategy is highly efficient for tuning the MA performance of MXene-based microspheres.
基金financially supported by the National Natural Science Foundation of China (No.52172218)。
文摘Cation additives can efficiently enhance the total electrochemical capabilities of zinc-ion hybrid capacitors (ZHCs).However their energy storage mechanisms in zinc-based systems are still under debate.Herein,we modulate the electrolyte and achieve dual-ion storage by adding magnesium ions.And we assemble several Zn//activated carbon devices with different electrolyte concentrations and investigate their electrochemical reaction dynamic behaviors.The zinc-ion capacitor with Mg^(2+)mixed solution delivers 82 mAh·g^(-1)capacity at 1 A·g^(-1) and maintains 91%of the original capacitance after 10000 cycling.It is superior to the other assembled zinc-ion devices in single-component electrolytes.The finding demonstrates that the double-ion storage mechanism enables the superior rate performance and long cycle lifetime of ZHCs.
基金financially supported by the National Natural Science Foundation of China(Nos.51872005,52072002 and 22108003)the Natural Science Foundation of Anhui Provincial Education Department(No.KJ2021A0401)+1 种基金WanJiang Scholar ProgramAnhui International Research Center of Energy Materials Green Manufacturing and Biotechnology。
文摘Developing electrochemical energy storage devices with high energy and power densities,long cycling life,as well as low cost is of great significance.Hybrid metal-ion capacitors(MICs),commonly consisting of high energy battery-type anodes and high power capacitor-type cathodes,have become a trade-off between batteries and supercapacitors.Tremendous efforts have been devoted to searching for high-performance electrode materials due to poor rate capability of anodes,low capacity of cathodes,and interior sluggish kinetic match.Carbon materials with large surface area,good electrical conductivity and stability have been considered to be ideal candidates for electrodes of MICs.In this review,the advanced carbon materials directly as cathodes and anodes of MICs are systematically summarized.Then,the key structural/chemical factors including the structure engineering,porous characteristics,and heteroatom incorporation for improving electrochemical performance of carbon materials are highlighted.Additionally,the challenges and opportunities for future research on carbon materials in MICs are also proposed.
