New electrochemical energy storage systems have stringent requirements for energy storage materials,and traditional MnO_(2) cannot comply with the requirements because of the problems of electrical conductivity and ph...New electrochemical energy storage systems have stringent requirements for energy storage materials,and traditional MnO_(2) cannot comply with the requirements because of the problems of electrical conductivity and phase transition.In this work,a novel polypyrrole(PPy)intercalation MnO_(2)(MnO_(2)/PPy-x)material was prepared and proved to be suitable for use in a high performance cathode of aqueous zinc ion batteries(AZIBs).The material characterization results proved that PPy played a key role between MnO_(2) layers,and the reduction of Mn and extension of Mn-O bonds inhibited the distortion reaction of MnO_(2),resulting in enhanced structural stability and excellent cycle life.In addition,electrochemical analysis revealed the H+/Zn2+co-intercalation mechanism,and MnO_(2)/PPy-1 had high electrical conductivity,and fast reaction kinetics.Density functional theory(DFT)calculation proved the change of electron distribution between the MnO_(2) layers.The PPy endowed MnO_(2) with excellent electrical conductivity.Moreover,as an interlayer spacer,it hindered charge transfer and decreased the binding ability of Zn2+and MnO_(2).As a result,the electrochemical performance of MnO_(2)/PPy-1 was greatly enhanced.The final results demonstrated that MnO_(2)/PPy-1,which has a high conductivity and wide layer spacing,offered a superior capacity of 234 mA h g^(-1) and a long cycle life of 2000 cycles at a current density of 1 A g^(-1).In addition,according to the test results of pouch batteries,MnO_(2)/PPy-1 shows great potential for the flexible device market because of its superior flexibility and safety.This work provides a new method and approach for the modification of MnO_(2)-based materials.展开更多
Traditional pyrotechnic compositions formed by mechanically mixing flammable and oxidative agents face the problems of complex formulations,inaccurate chemical stoichiometry,and inefficient colour-producing reactions....Traditional pyrotechnic compositions formed by mechanically mixing flammable and oxidative agents face the problems of complex formulations,inaccurate chemical stoichiometry,and inefficient colour-producing reactions.Emerging molecular perovskite energetic materials with embedded ternary ions have evolved into a new platform for developing explosives,propellants,ignition materials,and energetic biocides,taking advantage of their easy preparation and high adjustability.However,their potential in pyrotechnic applications has not yet been investigated.Herein,by assembling barium(II)perchlorate with imidazolium(Him+)and quinuclidinium(Hqe^(+))ions,we obtained two new energetic compounds,(Him)(Ba)(ClO_(4))_(3)(IBP)with a cubic perovskite structure,and(Hqe)_(2)(Ba)(ClO_(4))_(4)(QBP)with a layered perovskite structure.Both IBP and QBP have decomposition peak temperatures exceeding 290℃ and much higher moisture stabilities than barium perchlorate.With a layered structure,QBP has significantly lower friction sensitivity(144 N)than IBP(5 N).Moreover,the tight stacking of barium(II),oxidative perchlorate ions,and carbon-rich fuel components at the molecular level allows QBP to exhibit high-efficiency and stable combustion,outputting a maximum combustion pressure of up to 550 kPa,a maximum pressure pulse rate of up to 10.48 MPa s^(-1),and a bright green flame.These findings demonstrate well that molecular perovskite energetic compounds integrating a luminescent component,oxidative anions,and organic cations are promising contenders for next-generation pyrotechnic materials.展开更多
基金supported the National Natural Science Foundation of China(Grant No.62101296 and 52303335)the China Postdoctoral Science Foundation(2021M702656 and 2023M730099)+1 种基金the Natural Science Foundation of Shaanxi Province(Grant No.2021JQ-756 and 2023-JC-QN0577)the Graduate Innovation Fund of the School of Mechanical Engineering,Shaanxi University of Technology(SLGJX202404).
文摘New electrochemical energy storage systems have stringent requirements for energy storage materials,and traditional MnO_(2) cannot comply with the requirements because of the problems of electrical conductivity and phase transition.In this work,a novel polypyrrole(PPy)intercalation MnO_(2)(MnO_(2)/PPy-x)material was prepared and proved to be suitable for use in a high performance cathode of aqueous zinc ion batteries(AZIBs).The material characterization results proved that PPy played a key role between MnO_(2) layers,and the reduction of Mn and extension of Mn-O bonds inhibited the distortion reaction of MnO_(2),resulting in enhanced structural stability and excellent cycle life.In addition,electrochemical analysis revealed the H+/Zn2+co-intercalation mechanism,and MnO_(2)/PPy-1 had high electrical conductivity,and fast reaction kinetics.Density functional theory(DFT)calculation proved the change of electron distribution between the MnO_(2) layers.The PPy endowed MnO_(2) with excellent electrical conductivity.Moreover,as an interlayer spacer,it hindered charge transfer and decreased the binding ability of Zn2+and MnO_(2).As a result,the electrochemical performance of MnO_(2)/PPy-1 was greatly enhanced.The final results demonstrated that MnO_(2)/PPy-1,which has a high conductivity and wide layer spacing,offered a superior capacity of 234 mA h g^(-1) and a long cycle life of 2000 cycles at a current density of 1 A g^(-1).In addition,according to the test results of pouch batteries,MnO_(2)/PPy-1 shows great potential for the flexible device market because of its superior flexibility and safety.This work provides a new method and approach for the modification of MnO_(2)-based materials.
基金supported by NSFC(U2341287 and 22488101)Guangzhou Science and Technology Programme(2024A04J6499)Fundamental Research Funds for the Central Universities,Sun Yat-Sen University(23lgzy001).
文摘Traditional pyrotechnic compositions formed by mechanically mixing flammable and oxidative agents face the problems of complex formulations,inaccurate chemical stoichiometry,and inefficient colour-producing reactions.Emerging molecular perovskite energetic materials with embedded ternary ions have evolved into a new platform for developing explosives,propellants,ignition materials,and energetic biocides,taking advantage of their easy preparation and high adjustability.However,their potential in pyrotechnic applications has not yet been investigated.Herein,by assembling barium(II)perchlorate with imidazolium(Him+)and quinuclidinium(Hqe^(+))ions,we obtained two new energetic compounds,(Him)(Ba)(ClO_(4))_(3)(IBP)with a cubic perovskite structure,and(Hqe)_(2)(Ba)(ClO_(4))_(4)(QBP)with a layered perovskite structure.Both IBP and QBP have decomposition peak temperatures exceeding 290℃ and much higher moisture stabilities than barium perchlorate.With a layered structure,QBP has significantly lower friction sensitivity(144 N)than IBP(5 N).Moreover,the tight stacking of barium(II),oxidative perchlorate ions,and carbon-rich fuel components at the molecular level allows QBP to exhibit high-efficiency and stable combustion,outputting a maximum combustion pressure of up to 550 kPa,a maximum pressure pulse rate of up to 10.48 MPa s^(-1),and a bright green flame.These findings demonstrate well that molecular perovskite energetic compounds integrating a luminescent component,oxidative anions,and organic cations are promising contenders for next-generation pyrotechnic materials.
