MnO_(2) stands out among cathode materials for aqueous zinc-ion batteries(AZIBs)high capacity and voltage,it has poor stability and slow Zn^(2+) kinetics.Herein,we propose a dual-regulation strategy integrating copper...MnO_(2) stands out among cathode materials for aqueous zinc-ion batteries(AZIBs)high capacity and voltage,it has poor stability and slow Zn^(2+) kinetics.Herein,we propose a dual-regulation strategy integrating copper doping and carbon-based confinement.Residual carbon(RC),derived from acid-washed coal gasification fine slag(CGFS),serves as a conductive and porous framework for the directional growth of Cu-doped MnO_(2) nanowires(CMO@RC).The synergistic modulation of Cu-induced electronic structure tuning and carbon confinement induced mechanical/electrical stabilization significantly enhances Zn^(2+) transport and electrochemical performance.CMO@RC achieves a high capacity of 563 mA·h·g^(−1) at 0.1 A·g^(−1) and maintains 106%after 1000 cycles at 1 A·g^(−1).Kinetic analyses confirm the dual-path Zn^(2+) diffusion and accelerated reaction kinetics,while DFT calculations reveal that Cu doping enhances Mn 3d orbital hybridization and electron interaction with carbon,elevating the density of states near the Fermi level and reducing charge transfer barriers.Furthermore,pouch cell testing demonstrates outstanding flexibility and mechanical resilience.This study provides a cost-effective and scalable strategy for high-performance AZIBs,leveraging both experimental and theoretical validations.展开更多
The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering c...The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.展开更多
MnO_(2) emerges as a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity and ideal working voltage.However,inherent limitations in low electrical conductivity and struc...MnO_(2) emerges as a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity and ideal working voltage.However,inherent limitations in low electrical conductivity and structural instability restrict its widespread application.Herein,we fabricated layered δ-MnO_(2) and introduced Cu and Ce metal ions for structural regulation,thus constructing a δ/a-MnO_(2) heterostructure within the δ-MnO_(2) matrix,forming a heterointerface that simultaneously enhances the electrical conductivity and structural stability of the material.In this system,Cu^(2+)acts as a catalyst,promoting the reduction of high-valent Mn to Mn^(2+)and enabling local two-electron transfer,which significantly increases the discharge specific capacity of MnO_(2).For Ce^(3+),it functions as a structural regulator,inducing the partial transformation of δ-MnO_(2) to a-MnO_(2) and forming the δ/a-MnO_(2) heterostructure.Further supported by density functional theory(DFT)calculations and in-situ characterization results,the heterointerface between a-MnO_(2) andδ-MnO_(2) generates an internal electric field due to the difference in Fermi levels.This not only effectively enhances the electron transfer capability but also significantly improves structural stability.Benefiting from these advantages,the Cu,Ce co-incorporated MnO_(2)(CCMO)cathode delivers a high discharge capacity of 455.4 mAh g^(-1)at 0.2 A g^(-1)and maintains 191.2 mAh g^(-1)specific capacity after 1500 cycles with 95%capacity retention at 2 A g^(-1),which is significantly better than non-doped MnO_(2).This strategy of structural regulation and heterostructure construction using vip ions offers a new approach for developing high-performance Mn-based cathode materials for AZIBs.展开更多
基金support from the Key projects of scientific research projects of universities in Anhui Province(2024AH050360).
文摘MnO_(2) stands out among cathode materials for aqueous zinc-ion batteries(AZIBs)high capacity and voltage,it has poor stability and slow Zn^(2+) kinetics.Herein,we propose a dual-regulation strategy integrating copper doping and carbon-based confinement.Residual carbon(RC),derived from acid-washed coal gasification fine slag(CGFS),serves as a conductive and porous framework for the directional growth of Cu-doped MnO_(2) nanowires(CMO@RC).The synergistic modulation of Cu-induced electronic structure tuning and carbon confinement induced mechanical/electrical stabilization significantly enhances Zn^(2+) transport and electrochemical performance.CMO@RC achieves a high capacity of 563 mA·h·g^(−1) at 0.1 A·g^(−1) and maintains 106%after 1000 cycles at 1 A·g^(−1).Kinetic analyses confirm the dual-path Zn^(2+) diffusion and accelerated reaction kinetics,while DFT calculations reveal that Cu doping enhances Mn 3d orbital hybridization and electron interaction with carbon,elevating the density of states near the Fermi level and reducing charge transfer barriers.Furthermore,pouch cell testing demonstrates outstanding flexibility and mechanical resilience.This study provides a cost-effective and scalable strategy for high-performance AZIBs,leveraging both experimental and theoretical validations.
基金supported by the National Natural Science Foundation of China(22409065)the Guangdong Basic and Applied Basic Research Foundation(2022A1515011906)+2 种基金the China Postdoctoral Science Foundation(2023M731153)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technologythe Postdoctoral Fellowship Program of CPSF(GZC20230868).
文摘The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.
基金supported by the National Natural Science Foundation of China(no.52574348)the Natural Science Foundation of Hebei Province(nos.E2024501010 and B2024501004)+3 种基金the Shijiazhuang Basic Research Project(no.241790667A)the Fundamental Research Funds for the Central Universities(no.N2423013)the National College Students Innovation and Entrepreneurship Training Program(no.202419145017)the Performance Subsidy Fund for Key Laboratory of Dielectric,Electrolyte Functional Material Hebei Province(no.22567627H)。
文摘MnO_(2) emerges as a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity and ideal working voltage.However,inherent limitations in low electrical conductivity and structural instability restrict its widespread application.Herein,we fabricated layered δ-MnO_(2) and introduced Cu and Ce metal ions for structural regulation,thus constructing a δ/a-MnO_(2) heterostructure within the δ-MnO_(2) matrix,forming a heterointerface that simultaneously enhances the electrical conductivity and structural stability of the material.In this system,Cu^(2+)acts as a catalyst,promoting the reduction of high-valent Mn to Mn^(2+)and enabling local two-electron transfer,which significantly increases the discharge specific capacity of MnO_(2).For Ce^(3+),it functions as a structural regulator,inducing the partial transformation of δ-MnO_(2) to a-MnO_(2) and forming the δ/a-MnO_(2) heterostructure.Further supported by density functional theory(DFT)calculations and in-situ characterization results,the heterointerface between a-MnO_(2) andδ-MnO_(2) generates an internal electric field due to the difference in Fermi levels.This not only effectively enhances the electron transfer capability but also significantly improves structural stability.Benefiting from these advantages,the Cu,Ce co-incorporated MnO_(2)(CCMO)cathode delivers a high discharge capacity of 455.4 mAh g^(-1)at 0.2 A g^(-1)and maintains 191.2 mAh g^(-1)specific capacity after 1500 cycles with 95%capacity retention at 2 A g^(-1),which is significantly better than non-doped MnO_(2).This strategy of structural regulation and heterostructure construction using vip ions offers a new approach for developing high-performance Mn-based cathode materials for AZIBs.
