Lithium sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density,but still facing challenges.In order to make Li-S batter...Lithium sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density,but still facing challenges.In order to make Li-S batteries more competitive,combination of trapping sites and electrocatalytic properties for polysulfides is an effective way to improve the battery performance.In this study,we prepare a type of multifunctional V3S4-nanowire/graphene composites(V3S4-G)by uniformly dispersing V3S4 nanowires on the graphene substrate.This structure contributes to the sufficient exposure of multifunctional V3S4 active sites which can anchor polysulfides and accelerate reaction kinetics.Thus,the Li-S batteries based on the multifunctional V3S4-G sulfur cathode deliver a stable cycling performance and good rate capability.Even at sulfur loading of 3 mg cm^−2,the V3S4-G sulfur cathode possesses a low capacity decay rate of 0.186%per cycle at 0.5 C.展开更多
Na-ion batteries(SIBs)have attracted considerable attention as promising alternatives to commercial Li-ion batteries(LIBs)due to comparable redox potential,and natural abundance of Na.However,it remains challenging to...Na-ion batteries(SIBs)have attracted considerable attention as promising alternatives to commercial Li-ion batteries(LIBs)due to comparable redox potential,and natural abundance of Na.However,it remains challenging to explore suitable anodes for SIBs.Herein,a MoO2/N-doped carbon(MoO2/N-C)composite composed of MoO2 nanocrystals embedded within carbon matrix with a Mo–N–C chemical bond is prepared by a simple yet effective carbonization-induced topochemical transformation route.Na-ion half-cells using MoO2/N-C exhibit excellent cycling stability over 5000 cycles at 5 A g^-1 and superior rate capability.Physicochemical characterizations and first-principles density functional theory(DFT)simulations reveal that the formation of chemical bond at the interface between MoO2 and N-doped carbon plays an important role in the excellent charge storage properties of MoO2/N-C.More importantly,the interfacial coupling can efficiently promote interface charge transfer.Benefiting from this,Na-ion capacitors(SICs)constructed with the MoO2/N-C anode and activated carbon cathode can deliver an impressive energy density of 15 W h kg^-1 at a power density of 1760 W kg^-1,together with a capacitance retention of 92.4%over 1000 cycles at 10 A g^-1.The proposed strategy in this paper based on interfacial chemical bond may hold promises for the design of high-performance electrodes for energy storage devices.展开更多
基金We acknowledge the financial support from the National Key R&D Program of China(2016YFA0200102 and 2017YFA0206301)the National Natural Science Foundation of China(51631001,51590882,51672010 and 81421004).
文摘Lithium sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density,but still facing challenges.In order to make Li-S batteries more competitive,combination of trapping sites and electrocatalytic properties for polysulfides is an effective way to improve the battery performance.In this study,we prepare a type of multifunctional V3S4-nanowire/graphene composites(V3S4-G)by uniformly dispersing V3S4 nanowires on the graphene substrate.This structure contributes to the sufficient exposure of multifunctional V3S4 active sites which can anchor polysulfides and accelerate reaction kinetics.Thus,the Li-S batteries based on the multifunctional V3S4-G sulfur cathode deliver a stable cycling performance and good rate capability.Even at sulfur loading of 3 mg cm^−2,the V3S4-G sulfur cathode possesses a low capacity decay rate of 0.186%per cycle at 0.5 C.
基金supported by the National Natural Science Foundation of China(51804089)the Guangxi Key Laboratory of Electrochemical and Magneto-chemical Functional Materials(EMFM20181114)the support of the research starting foundation of CAEP(PY20200038)。
文摘Na-ion batteries(SIBs)have attracted considerable attention as promising alternatives to commercial Li-ion batteries(LIBs)due to comparable redox potential,and natural abundance of Na.However,it remains challenging to explore suitable anodes for SIBs.Herein,a MoO2/N-doped carbon(MoO2/N-C)composite composed of MoO2 nanocrystals embedded within carbon matrix with a Mo–N–C chemical bond is prepared by a simple yet effective carbonization-induced topochemical transformation route.Na-ion half-cells using MoO2/N-C exhibit excellent cycling stability over 5000 cycles at 5 A g^-1 and superior rate capability.Physicochemical characterizations and first-principles density functional theory(DFT)simulations reveal that the formation of chemical bond at the interface between MoO2 and N-doped carbon plays an important role in the excellent charge storage properties of MoO2/N-C.More importantly,the interfacial coupling can efficiently promote interface charge transfer.Benefiting from this,Na-ion capacitors(SICs)constructed with the MoO2/N-C anode and activated carbon cathode can deliver an impressive energy density of 15 W h kg^-1 at a power density of 1760 W kg^-1,together with a capacitance retention of 92.4%over 1000 cycles at 10 A g^-1.The proposed strategy in this paper based on interfacial chemical bond may hold promises for the design of high-performance electrodes for energy storage devices.
