Recently,abundant resources,low-cost sodium-ion batteries are deemed to the new-generation battery in the field of largescale energy storage.Nevertheless,poor active reaction dynamics,dissolution of intermediates and ...Recently,abundant resources,low-cost sodium-ion batteries are deemed to the new-generation battery in the field of largescale energy storage.Nevertheless,poor active reaction dynamics,dissolution of intermediates and electrolyte matching problems are significant challenges that need to be solved.Herein,dimensional gradient structure of sheet-tube-dots is constructed with CoSe2@CNTs-MXene.Gradient structure is conducive to fast migration of electrons and ions with the association of ether electrolyte.For half-cell,CoSe2@CNTs-MXene exhibits high initial coulomb efficiency(81.7%)and excellent cycling performance(400 mAh g^-1 cycling for 200 times in 2 Ag^−1).Phase transformation pathway from crystalline CoSe2-Na2Se with Co and then amorphous CoSe2 in the discharge/charge process is also explored by in situ X-ray diffraction.Density functional theory study discloses the CoSe2@CNTs-MXene in ether electrolyte system which contributes to stable sodium storage performance owing to the strong adsorption force from hierarchical structure and weak interaction between electrolyte and electrode interface.For full cell,CoSe2@CNTs-MXene//Na3V2(PO4)3/C full battery can also afford a competitively reversible capacity of 280 mAh g^−1 over 50 cycles.Concisely,profiting from dimensional gradient structure and matched electrolyte of CoSe2@CNTs-MXene hold great application potential for stable sodium storage.展开更多
The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to dri...The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to drive hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is extremely significant to promote overall water splitting.Herein,ultrathin CoSe2/CNTs nanocomposites have been synthesized by a facile two-step method,where the ultrathin Co-MOF(metal organic-framework)decorated with cable-like carbon nanotubes(CNTs)(Co-MOF/CNTs)was initially fabricated,and followed a lowtemperature selenization process.The ultrathin CoSe2 nanosheets as well as the superior conductivity of CNTs synergistically resulted in abundant active sites and enhanced conductivity to boost the electrocatalytic activity.The as-prepared CoSe2/CNTs electrocatalysts exhibited an overpotential of190 mV and 300 mV vs.reversible hydrogen electrode(RHE)at a current density of 10 mA/cm^(2) for the HER and OER in alkaline solution,respectively,and demonstrated superior durability.Furthermore,the as-prepared bifunctional CoSe2/CNTs electrocatalysts can act as cathode and anode in an electrolyzer,showing a cell voltage of 1.75 V at 10 mA/cm^(2) for overall water splitting.展开更多
Photocathode with superior catalytic activity,long-term stability,and fast mass/electron transfer is highly desirable but challenging for dye-sensitized solar cell(DSC).Herein,the ZIF-67 grown on carbon cloth is succe...Photocathode with superior catalytic activity,long-term stability,and fast mass/electron transfer is highly desirable but challenging for dye-sensitized solar cell(DSC).Herein,the ZIF-67 grown on carbon cloth is successfully transformed into CoSe2 embedded in N-doped carb on nano cage(CoSe2/N-C)via a growth-carbonization-selenization process.The carb on cloth supported CoSe2/N-C,as photocathode of DSC,demonstrates a good long-term stability and high photovoltaic efficiency(8.40%),outperforming Pt.The good efficiency can be attributed to the high catalytic activity of CoSe2,fast mass tran sfer of porous three-dimensi on al(3D)structure,and good electr on transport derived from the intimate con tact between CoSe2 and highly conductive carb on cloth.The high stability would be ascribed to N-doped carbon coating that perfectly prevents CoSe2 from decomposition.This work will pave the way to develop highly efficient and stable Pt-free photocathode for DSC.展开更多
Hydrogen evolution reaction(HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future.CoSe_2, one of th...Hydrogen evolution reaction(HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future.CoSe_2, one of the earth-abundant electrocatalysts, has been proved to be a promising catalyst for hydrogen generation. In our work, flower-like CoSe_2 nanorods with high quality are successfully synthesized through a facile ethylenediaminetetraacetic acid ligand(EDTA)-assisted hydrothermal process. The flower-like CoSe_2 nanorods show the brilliant electrochemical HER performance with 100 mA cm^(-2) at overpotential of 273 m V, a small Tafel slope of 35 mV dec^(-1) and strong durability in acid solution. The sparkly HER catalytic activity of CoSe_2 can be ascribed to its particular structure with large surface area and abundant active sites. Therefore, this work offers an outstanding candidate for improving hydrogen production capabilities by water electrolysis.展开更多
Rational electrode structure design is of great significance for realizing superior Na^(+)storage performance.Herein,a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed...Rational electrode structure design is of great significance for realizing superior Na^(+)storage performance.Herein,a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed to in-situ generate abundant sub-10 nm CoSe_(2) nanocrystals on 3D Se/N co-doped carbon networks(CoSe_(2)@3DSNC).The phase transition from Co to CoSe_(2) and the incorporation of Se into the carbon layer are realized simultaneously to establish above configuration,in which the CoSe_(2) nanocrystals are anchored on interlayer expanded carbon networks.Such unique configuration endows electrode with lower Na+diffusion energy barrier,higher Na+storage capability and better structural durability.Reflected in SIBs,the optimized CoSe_(2)@3 DSNC delivers superior rate capability(310 m Ah g^(-1) at 10 A g^(-1))and excellent longterm cycling stability(409 m Ah g^(-1) after 1200 cycles at 5 A g^(-1)).Moreover,this configuration can also be obtained in other metal selenides-carbon composite through a similar approach.展开更多
Sodium-ion batteries(SIBs)are an attractive battery system because of similar characteristics to lithium-ion batteries(LIBs)and large Na element abundance.Nevertheless,exploring stable,high-capacity and high-rate anod...Sodium-ion batteries(SIBs)are an attractive battery system because of similar characteristics to lithium-ion batteries(LIBs)and large Na element abundance.Nevertheless,exploring stable,high-capacity and high-rate anode materials for SIBs is still challenging now.Herein,diethylenetriamine(DETA)molecular template derived ultrathin N-doped carbon(NC)layer decorated CoSe_(2)nanobelts(CoSe_(2)/NC)are prepared by solvothermal reaction followed by calcination process.The CoSe_(2)/NC exhibits large potential as an anode for SIBs.Experiments and theoretical calculations reveal that the in situ formed conductive ultrathin NC layer can not only relieve the volume change of CoSe_(2)but also accelerate electron and ion transport.In addition,the nanobelt structure of CoSe_(2)/NC with abundant exposed active sites can obviously accelerate the electrochemical kinetics.Under the synergistic effect of special nanobelt structure and NC layer,the rate as well as cycling performances of CoSe_(2)/NC are obviously improved.A superior capacity retention of 94.8%is achieved at 2 A·g^(-1)after 2000 cycles.When using Na3V2(PO4)3 cathodes,the pouch full batteries can work steadily at 0.5 C,verifying the application ability.CoSe_(2)/NC anodes also exhibit impressive performances in LIBs and potassium-ion batteries(PIBs).展开更多
Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb fa...Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb facet of orthorhombic CoSe_(2) for OER. Afterwards, CoSe_(2)(001) nanosheets were synthesized and the exposure ratio of (001) facet is controllable with thermodynamics methods effectively. The single-facet CoSe2(001) delivered an overpotential as low as 240 mV at 10 mA·cm^(−2) in 1 M KOH, which outperformed the bulk (380 mV) as well as other CoSe_(2)-base OER catalysts reported before. Especially, a shorter Co-Co path was observed in CoSe_(2)(001) by X-ray absorption spectroscopy. Further density functional theory (DFT) studies revealed that the reversible compression on the shorter Co-Co path could regulate the electronic structure of active sites during the OER process, and thus the energy barrier of the rate-determining step was reduced by 0.15 eV. This work could inspire more insights on the modification of electronic structure for OER electrocatalysts.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U1632151 and 21706048)the Key Research and Development Project of Anhui Province of China(Grant No.1704a0902023)the Open Project of Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices(No.JS1802)。
文摘Recently,abundant resources,low-cost sodium-ion batteries are deemed to the new-generation battery in the field of largescale energy storage.Nevertheless,poor active reaction dynamics,dissolution of intermediates and electrolyte matching problems are significant challenges that need to be solved.Herein,dimensional gradient structure of sheet-tube-dots is constructed with CoSe2@CNTs-MXene.Gradient structure is conducive to fast migration of electrons and ions with the association of ether electrolyte.For half-cell,CoSe2@CNTs-MXene exhibits high initial coulomb efficiency(81.7%)and excellent cycling performance(400 mAh g^-1 cycling for 200 times in 2 Ag^−1).Phase transformation pathway from crystalline CoSe2-Na2Se with Co and then amorphous CoSe2 in the discharge/charge process is also explored by in situ X-ray diffraction.Density functional theory study discloses the CoSe2@CNTs-MXene in ether electrolyte system which contributes to stable sodium storage performance owing to the strong adsorption force from hierarchical structure and weak interaction between electrolyte and electrode interface.For full cell,CoSe2@CNTs-MXene//Na3V2(PO4)3/C full battery can also afford a competitively reversible capacity of 280 mAh g^−1 over 50 cycles.Concisely,profiting from dimensional gradient structure and matched electrolyte of CoSe2@CNTs-MXene hold great application potential for stable sodium storage.
基金the financial support by the National Natural Science Foundation of China(No.21771137)the Key Project of Natural Science Foundation of Tianjin(No.18JCZDJC97200)+1 种基金the Training Project of Innovation Team of Colleges and Universities in Tianjin(No.TD13-5020)the start-up fund of Qilu University of Technology,Shandong Academy of Sciences。
文摘The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to drive hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is extremely significant to promote overall water splitting.Herein,ultrathin CoSe2/CNTs nanocomposites have been synthesized by a facile two-step method,where the ultrathin Co-MOF(metal organic-framework)decorated with cable-like carbon nanotubes(CNTs)(Co-MOF/CNTs)was initially fabricated,and followed a lowtemperature selenization process.The ultrathin CoSe2 nanosheets as well as the superior conductivity of CNTs synergistically resulted in abundant active sites and enhanced conductivity to boost the electrocatalytic activity.The as-prepared CoSe2/CNTs electrocatalysts exhibited an overpotential of190 mV and 300 mV vs.reversible hydrogen electrode(RHE)at a current density of 10 mA/cm^(2) for the HER and OER in alkaline solution,respectively,and demonstrated superior durability.Furthermore,the as-prepared bifunctional CoSe2/CNTs electrocatalysts can act as cathode and anode in an electrolyzer,showing a cell voltage of 1.75 V at 10 mA/cm^(2) for overall water splitting.
基金the National Natural Science Foundation of China(Nos.21725501,21771019,21475007 and 21675009)the Fundamental Research Funds for the Central Universities(Nos.buctrc201706,buctrc201815 and buctrc201812).
文摘Photocathode with superior catalytic activity,long-term stability,and fast mass/electron transfer is highly desirable but challenging for dye-sensitized solar cell(DSC).Herein,the ZIF-67 grown on carbon cloth is successfully transformed into CoSe2 embedded in N-doped carb on nano cage(CoSe2/N-C)via a growth-carbonization-selenization process.The carb on cloth supported CoSe2/N-C,as photocathode of DSC,demonstrates a good long-term stability and high photovoltaic efficiency(8.40%),outperforming Pt.The good efficiency can be attributed to the high catalytic activity of CoSe2,fast mass tran sfer of porous three-dimensi on al(3D)structure,and good electr on transport derived from the intimate con tact between CoSe2 and highly conductive carb on cloth.The high stability would be ascribed to N-doped carbon coating that perfectly prevents CoSe2 from decomposition.This work will pave the way to develop highly efficient and stable Pt-free photocathode for DSC.
基金financially supported by the National Natural Science Foundation of China (No. 21675131, 21273174)the Municipal Science Foundation of Chongqing City (No. CSTC2015jcyjB50001)
文摘Hydrogen evolution reaction(HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future.CoSe_2, one of the earth-abundant electrocatalysts, has been proved to be a promising catalyst for hydrogen generation. In our work, flower-like CoSe_2 nanorods with high quality are successfully synthesized through a facile ethylenediaminetetraacetic acid ligand(EDTA)-assisted hydrothermal process. The flower-like CoSe_2 nanorods show the brilliant electrochemical HER performance with 100 mA cm^(-2) at overpotential of 273 m V, a small Tafel slope of 35 mV dec^(-1) and strong durability in acid solution. The sparkly HER catalytic activity of CoSe_2 can be ascribed to its particular structure with large surface area and abundant active sites. Therefore, this work offers an outstanding candidate for improving hydrogen production capabilities by water electrolysis.
基金financially supported by the National Natural Science Foundation of China(21471040)。
文摘Rational electrode structure design is of great significance for realizing superior Na^(+)storage performance.Herein,a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed to in-situ generate abundant sub-10 nm CoSe_(2) nanocrystals on 3D Se/N co-doped carbon networks(CoSe_(2)@3DSNC).The phase transition from Co to CoSe_(2) and the incorporation of Se into the carbon layer are realized simultaneously to establish above configuration,in which the CoSe_(2) nanocrystals are anchored on interlayer expanded carbon networks.Such unique configuration endows electrode with lower Na+diffusion energy barrier,higher Na+storage capability and better structural durability.Reflected in SIBs,the optimized CoSe_(2)@3 DSNC delivers superior rate capability(310 m Ah g^(-1) at 10 A g^(-1))and excellent longterm cycling stability(409 m Ah g^(-1) after 1200 cycles at 5 A g^(-1)).Moreover,this configuration can also be obtained in other metal selenides-carbon composite through a similar approach.
基金supported by the National Natural Science Foundation of China(Nos.U21A2077 and 51972198)the State Key Program of National Natural Science of China(No.62133007)+3 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2021ZD05,ZR2020JQ19,ZR2022JQ08 and ZR2023QB169)Taishan Scholars Program of Shandong Province(Nos.tsqn201812002,ts20190908 and tsqn202211028)Shenzhen Fundamental Research Program(No.JCYJ20190807093405503)China Postdoctoral Science Foundation(No.2022M721913).
文摘Sodium-ion batteries(SIBs)are an attractive battery system because of similar characteristics to lithium-ion batteries(LIBs)and large Na element abundance.Nevertheless,exploring stable,high-capacity and high-rate anode materials for SIBs is still challenging now.Herein,diethylenetriamine(DETA)molecular template derived ultrathin N-doped carbon(NC)layer decorated CoSe_(2)nanobelts(CoSe_(2)/NC)are prepared by solvothermal reaction followed by calcination process.The CoSe_(2)/NC exhibits large potential as an anode for SIBs.Experiments and theoretical calculations reveal that the in situ formed conductive ultrathin NC layer can not only relieve the volume change of CoSe_(2)but also accelerate electron and ion transport.In addition,the nanobelt structure of CoSe_(2)/NC with abundant exposed active sites can obviously accelerate the electrochemical kinetics.Under the synergistic effect of special nanobelt structure and NC layer,the rate as well as cycling performances of CoSe_(2)/NC are obviously improved.A superior capacity retention of 94.8%is achieved at 2 A·g^(-1)after 2000 cycles.When using Na3V2(PO4)3 cathodes,the pouch full batteries can work steadily at 0.5 C,verifying the application ability.CoSe_(2)/NC anodes also exhibit impressive performances in LIBs and potassium-ion batteries(PIBs).
基金This work is supported by the financial support of the Beijing Natural Science Foundation(No.2182013)classification development at Capital Normal University(No.2155091).
文摘Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb facet of orthorhombic CoSe_(2) for OER. Afterwards, CoSe_(2)(001) nanosheets were synthesized and the exposure ratio of (001) facet is controllable with thermodynamics methods effectively. The single-facet CoSe2(001) delivered an overpotential as low as 240 mV at 10 mA·cm^(−2) in 1 M KOH, which outperformed the bulk (380 mV) as well as other CoSe_(2)-base OER catalysts reported before. Especially, a shorter Co-Co path was observed in CoSe_(2)(001) by X-ray absorption spectroscopy. Further density functional theory (DFT) studies revealed that the reversible compression on the shorter Co-Co path could regulate the electronic structure of active sites during the OER process, and thus the energy barrier of the rate-determining step was reduced by 0.15 eV. This work could inspire more insights on the modification of electronic structure for OER electrocatalysts.
