Manganese dioxide(MnO_(2))with different crystal structures has been widely investigated as the cathode material for Zn-ion batteries,among which spinelλ-MnO_(2)is yet rarely reported because Zn-ion intercalation in ...Manganese dioxide(MnO_(2))with different crystal structures has been widely investigated as the cathode material for Zn-ion batteries,among which spinelλ-MnO_(2)is yet rarely reported because Zn-ion intercalation in spinel lattice is speculated to be limited by the narrow three-dimensional tunnels.In this work,we demonstrate that Zn-ion insertion in spinel lattice can be enhanced by reducing particle size and elucidate an intriguing electrochemical reaction mechanism dependent on particle size.Specifically,λ-MnO_(2)nanoparticles(NPs,~80 nm)deliver a high capacity of 250 mAh/g at 20 mA/g due to large surface area and solid-solution type phase transition pathway.Meanwhile,severe water-induced Mn dissolution leads to the poor cycling stability of NPs.In contrast,micron-sizedλ-MnO_(2)particles(MPs,~0.9μm)unexpectedly undergo an activation process with the capacity continuously increasing over the first 50 cycles,which can be attributed to the formation of amorphous MnOx nanosheets in the open interstitial space of the MP electrode.By adding MnSO_(4)to the electrolyte,Mn dissolution can be suppressed,leading to significant improvement in the cycling performance of NPs,with a capacity of 115 mAh/g retained at 1 A/g for over 500 cycles.This work pinpoints the distinctive impacts of the particle size on the reaction mechanism and cathode performance in aqueous Zn-ion batteries.展开更多
CONSPECTUS:As a metal that can occur in nature in the elemental form,copper(Cu)has been used by humans since ca.8000 BC.With most properties matching those of Ag and Au,Cu has played a more significant role in commerc...CONSPECTUS:As a metal that can occur in nature in the elemental form,copper(Cu)has been used by humans since ca.8000 BC.With most properties matching those of Ag and Au,Cu has played a more significant role in commercial applications owing to its much higher(the 25th among all elements)abundance in Earth’s crust and thus more affordable price.In addition to its common use as a conductor of heat and electricity,it is a constituent of various metal alloys for hardware,coins,strain gauges,and thermocouples.展开更多
基金We thank Dr.Hyosung An for the help with the EIS measurements.This work was supported by the Energy&Biosciences Institute through the EBI-Shell program and the National Science Foundation under Grant No.1752517.Experiments were carried out in part in the Materials Research Laboratory Central Research Facilities,University of Illinois.
文摘Manganese dioxide(MnO_(2))with different crystal structures has been widely investigated as the cathode material for Zn-ion batteries,among which spinelλ-MnO_(2)is yet rarely reported because Zn-ion intercalation in spinel lattice is speculated to be limited by the narrow three-dimensional tunnels.In this work,we demonstrate that Zn-ion insertion in spinel lattice can be enhanced by reducing particle size and elucidate an intriguing electrochemical reaction mechanism dependent on particle size.Specifically,λ-MnO_(2)nanoparticles(NPs,~80 nm)deliver a high capacity of 250 mAh/g at 20 mA/g due to large surface area and solid-solution type phase transition pathway.Meanwhile,severe water-induced Mn dissolution leads to the poor cycling stability of NPs.In contrast,micron-sizedλ-MnO_(2)particles(MPs,~0.9μm)unexpectedly undergo an activation process with the capacity continuously increasing over the first 50 cycles,which can be attributed to the formation of amorphous MnOx nanosheets in the open interstitial space of the MP electrode.By adding MnSO_(4)to the electrolyte,Mn dissolution can be suppressed,leading to significant improvement in the cycling performance of NPs,with a capacity of 115 mAh/g retained at 1 A/g for over 500 cycles.This work pinpoints the distinctive impacts of the particle size on the reaction mechanism and cathode performance in aqueous Zn-ion batteries.
基金supported in part by the NSF(CHE-1804970,DMR-1505400,DMR-1506018,DMR-0804088,DMR-1104614,DMR-1215034)the NIH(R01,CA138527)+1 种基金the Department of Energy-Basic Energy Sciences,Division of Chemical Sciences(DE-FG02-05ER15731)startup funds from the Georgia Institute of Technology.We thank our collaborators for their invaluable contributions to these studies.
文摘CONSPECTUS:As a metal that can occur in nature in the elemental form,copper(Cu)has been used by humans since ca.8000 BC.With most properties matching those of Ag and Au,Cu has played a more significant role in commercial applications owing to its much higher(the 25th among all elements)abundance in Earth’s crust and thus more affordable price.In addition to its common use as a conductor of heat and electricity,it is a constituent of various metal alloys for hardware,coins,strain gauges,and thermocouples.
