Aqueous zinc-ion batteries have been regarded as the most potential candidate to substitute lithium-ion batteries.However,many serious challenges such as suppressing zinc dendrite growth and undesirable reactions,and ...Aqueous zinc-ion batteries have been regarded as the most potential candidate to substitute lithium-ion batteries.However,many serious challenges such as suppressing zinc dendrite growth and undesirable reactions,and achieving fully accepted mechanism also have not been solved.Herein,the commensal composite microspheres withα-MnO_(2) nano-wires and carbon nanotubes were achieved and could effectively suppress ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O rampant crystallization.The electrode assembled with the microspheres delivered a high initial capacity at a current density of 0.05 A g^(-1) and maintained a significantly prominent capacity retention of 88%over 2500 cycles.Furthermore,a novel energy-storage mechanism,in which multivalent manganese oxides play a synergistic effect,was comprehen-sively investigated by the quantitative and qualitative analysis for ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O.The capacity contribution of multivalent manganese oxides and the crystal structure dissection in the transformed processes were completely identified.Therefore,our research could provide a novel strategy for designing improved electrode structure and a comprehensive understanding of the energy storage mechanism of α-MnO_(2) cathodes.展开更多
The aqueous solution-based zinc-ion hybrid supercapacitors(ZHSCs)have attracted immense attention as they are characterized by high power and energy densities.Electrode materials with high performance should be develo...The aqueous solution-based zinc-ion hybrid supercapacitors(ZHSCs)have attracted immense attention as they are characterized by high power and energy densities.Electrode materials with high performance should be developed for ZHSCs to resolve power imbalances between capacitor-and battery-type electrode materials.To address this issue,Nb_(2)O_(5) microspheres(with the structure like sweet dumplings with exposed stuffing)were produced following a hydrothermal process which was followed by a high-temperature calcination process.The specific capacity of the as-synthesized Nb_(2)O_(5) microspheres was up to 324 F·g^(-1) when the current density was 0.1 A·g^(-1),and the long-term capacity retention was 85%at the end of 5000 cycles.The results revealed that the nanospheres could be used as battery-type electrode materials for the fabrication of ZHSCs.Nb_(2)O_(5)//AC ZHSCs were fabricated with Nb_(2)O_(5) microspheres as the negative electrode materials,and activated carbon(AC)was used as the positive electrode material.As a result,a specific capacity of 108 F·g^(-1) was achieved when the current density was 0.1 A·g^(-1).The power density was high(8020 W·kg^(-1))at 28 Wh·kg^(-1),and the energy density was high(60 Wh·kg^(-1))at 100 W·kg^(-1).The structurally novel Nb_(2)O_(5) microspheres can be potentially used for the development of the next-generation ZHSCs that exhibit excellent performance.展开更多
基金This work is supported by the National Nature Science Foundation of China(51972108,52171200)Changsha Special Project(kh2301006)the Education Department of Hunan Province(19C0576).
文摘Aqueous zinc-ion batteries have been regarded as the most potential candidate to substitute lithium-ion batteries.However,many serious challenges such as suppressing zinc dendrite growth and undesirable reactions,and achieving fully accepted mechanism also have not been solved.Herein,the commensal composite microspheres withα-MnO_(2) nano-wires and carbon nanotubes were achieved and could effectively suppress ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O rampant crystallization.The electrode assembled with the microspheres delivered a high initial capacity at a current density of 0.05 A g^(-1) and maintained a significantly prominent capacity retention of 88%over 2500 cycles.Furthermore,a novel energy-storage mechanism,in which multivalent manganese oxides play a synergistic effect,was comprehen-sively investigated by the quantitative and qualitative analysis for ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O.The capacity contribution of multivalent manganese oxides and the crystal structure dissection in the transformed processes were completely identified.Therefore,our research could provide a novel strategy for designing improved electrode structure and a comprehensive understanding of the energy storage mechanism of α-MnO_(2) cathodes.
基金financially supported by the National Natural Science Foundation of China(Nos.51972108 and 51772090)China Postdoctoral Science Foundation(No.2021M693777)+1 种基金the Natural Science Foundation of Hunan Province(No.2020JJ4272)the Education Department of Hunan Province(No.19C0576)。
文摘The aqueous solution-based zinc-ion hybrid supercapacitors(ZHSCs)have attracted immense attention as they are characterized by high power and energy densities.Electrode materials with high performance should be developed for ZHSCs to resolve power imbalances between capacitor-and battery-type electrode materials.To address this issue,Nb_(2)O_(5) microspheres(with the structure like sweet dumplings with exposed stuffing)were produced following a hydrothermal process which was followed by a high-temperature calcination process.The specific capacity of the as-synthesized Nb_(2)O_(5) microspheres was up to 324 F·g^(-1) when the current density was 0.1 A·g^(-1),and the long-term capacity retention was 85%at the end of 5000 cycles.The results revealed that the nanospheres could be used as battery-type electrode materials for the fabrication of ZHSCs.Nb_(2)O_(5)//AC ZHSCs were fabricated with Nb_(2)O_(5) microspheres as the negative electrode materials,and activated carbon(AC)was used as the positive electrode material.As a result,a specific capacity of 108 F·g^(-1) was achieved when the current density was 0.1 A·g^(-1).The power density was high(8020 W·kg^(-1))at 28 Wh·kg^(-1),and the energy density was high(60 Wh·kg^(-1))at 100 W·kg^(-1).The structurally novel Nb_(2)O_(5) microspheres can be potentially used for the development of the next-generation ZHSCs that exhibit excellent performance.
