Lattice oxygen participation is crucial for oxygen-evolution reaction(OER)performance,but stabilizing the active high-valence cation remains a major challenge.This study focuses on iron oxyhydroxide(FeOOH),which exhib...Lattice oxygen participation is crucial for oxygen-evolution reaction(OER)performance,but stabilizing the active high-valence cation remains a major challenge.This study focuses on iron oxyhydroxide(FeOOH),which exhibits a delicate balance between high-valence states and stability.A heterostructure(CeO_(2)/FeOOH)with an electron-rich,high-valence-state interface was synthesized via a simple co-precipitation method.Due to the work-function disparity between CeO_(2) and FeOOH,electron accumulation occurs in CeO_(2),while FeOOH attains a high-valence state.This enhanced valence state strengthens Fe–O covalency,facilitating lattice oxygen participation in oxygen-evolution reaction.Furthermore,electron-abundant CeO_(2) functions as a redox buffer,where the electron-reservable Ce3+/Ce4+redox couple stores excessive oxygen and donates electrons to stabilize high-valence FeOOH.By incorporating this“redox-buffering system,”Fe dissolution was minimized,significantly improving catalyst stability under harsh oxidizing conditions.The anion exchange membrane electrolyzer exhibited outstanding performance,delivering a current density of 500 mA cm^(-2) at 1.69 V,with remarkable stability over 100 h at 1 A cm^(-2).These findings provide a new strategy for stabilizing high-valence-state oxygen-evolution reaction catalysts,offering valuable insights for designing efficient and durable electrochemical systems.展开更多
Lithium and manganese-rich layered oxides(LMROs)have attracted extensive attention and are promising cathode materials for next-generation lithium ion batteries due to their high capacities and high energy densities.H...Lithium and manganese-rich layered oxides(LMROs)have attracted extensive attention and are promising cathode materials for next-generation lithium ion batteries due to their high capacities and high energy densities.However,LMRO cathode suffers from severe capacity and voltage fading originating from irreversible surface oxygen evolution.Herein,we propose a facile redox couple strategy by introducing nitroxyl radicals species to regulate the surface anionic redox reaction of LMRO cathode.Differential electrochemical mass spectroscopy,X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses demonstrate that during charge process,the peroxide ion O_(2)^(2−)on the surface generated from the oxidation of lattice O^(2-)could be reduced back to stable O^(2-)by redox couple in time,thus avoiding oxygen evolution and structure degradation,as well as enhancing bulk oxygen redox activity.The enhanced LMRO electrode delivers a high capacity of 220.3 mAh g^(−1)at 1 C.An excellent cycling stability with a capacity retention of 94.4%is achieved after 500 cycles,as well as a suppressed voltage decay with only 1.12 mV per cycle.展开更多
Thermocells are attracting growing interest as a promising thermoelectric technology for low-grade heat harvesting.However,the scarcity of high-performance redox couples featuring intrinsically high thermopower(Se)and...Thermocells are attracting growing interest as a promising thermoelectric technology for low-grade heat harvesting.However,the scarcity of high-performance redox couples featuring intrinsically high thermopower(Se)and fast redox kinetics hinders the rapid development of thermocells.Identifying potential intrinsically high-performance redox couples remains a significant challenge.This work introduces a novel n-type copper(I/II)chloride(CuCl/CuCl2)redox couple with intrinsically high performance.Through tailored electrolyte design,long-term stability was significantly improved by reducing proton concentration to suppress cuprous ion photo-oxidation,while ammonium chloride solvation enhanced cuprous ion solubility.The resulting system achieves a Se value closely aligned with theoretical predictions and exhibits rapid redox kinetics.Consequently,the optimized CuCl/CuCl_(2) intrinsic system demonstrated a high S_(e) of 1.52 mV K^(−1) and a record-high normalized power density Pmax(ΔT)^(−2) of 0.399 mW m^(−2) K^(−2),surpassing previously reported intrinsic n-type thermocells and rivaling the performance of p-type pristine 0.4 M ferri/ferrocyanide systems.A prototype module comprising 30 p-n units successfully powered a line of light-emitting diodes or a thermohygrometer.This work introduces a valuable redox couple for further advancing high-performance thermocells and demonstrates a viable strategy for developing novel redox systems.展开更多
Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)ph...Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)photocatalysts were successfully prepared via a simple in-situ doping method and exhibited superior PODS performance of dibenzothiophene(DBT)under mild reaction conditions.The 1.0 mol%Ce/MIL-125-NH_(2)catalyst achieved 100%sulfur removal within 22 min at 30℃ under visible light illumination,which is mainly attributed to the high surface area and the formation of Ce-Ti-oxo clusters due to electronic coupling.The valence transformation of Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators could not only expose abundant Lewis acid sites,but also promote the separation and transfer of photogenerated charges.In addition,increasing the reaction temperature has been demonstrated to be effective in promoting the PODS performance.Additionally,a thermo-enhanced PODS mechanism was proposed over Ce/MIL-125-NH_(2),demonstrating the great potential of thermal energy to promote the desulfurization activity.展开更多
Developing advanced secondary batteries with low cost and high safety has attracted increasing research interests across the world.In particular,the aqueous zinc-ion battery(AZIB)has been regarded as a promising candi...Developing advanced secondary batteries with low cost and high safety has attracted increasing research interests across the world.In particular,the aqueous zinc-ion battery(AZIB)has been regarded as a promising candidate owing to the high abundance and capacity of Zn metal.Currently,manganese-based and vanadium-based oxides are most common choices for cathode materials used in AZIBs,but they unfortunately show a moderate cell voltage and limited rate performance induced by slow intercalation-extraction kinetics of Zn^(2+)ions.To address these issues,alternative cathode systems with tunable redox potentials and intrinsic fast kinetics have been exploited.In the past few years,conversion-type cathodes of I_(2)and S have become the most illustrative examples to match or even surpass the performance of conventional metal oxide cathodes in AZIBs.Herein,we sum up most recent progress in conversion-type cathodes and focus on novel ideas and concepts in designing/modifying cathodes for AZIBs with high voltage/capacity.Additionally,potential directions and future efforts are tentatively proposed for further development of conversion-type cathodes,aiming to speed up the practical application of AZIBs.展开更多
Lithium-sulfur batteries(LSBs)have emerged as promising power sources for high-performance devices such as electric vehicles.However,the poor energy density of LSBs owing to polysulfide shuttling and passivation has l...Lithium-sulfur batteries(LSBs)have emerged as promising power sources for high-performance devices such as electric vehicles.However,the poor energy density of LSBs owing to polysulfide shuttling and passivation has limited their further market penetration.To mitigate this challenge,two-dimensional(2D)siloxene(2DSi),a Si-based analog of graphene,is utilized as an additive for sulfur cathodes.The 2DSi is fabricated on a large scale by simple solvent extraction of calcium disilicide to form a thin-layered structure of Si planes functionalized with vertically aligned hydroxyl groups in the 2DSi.The stoichiometric reaction of 2DSi with polysulfides generates a thiosulfate redox mediator,secures the intercalation pathway,and reveals Lewis acidic sites within the siloxene galleries.The 2DSi utilizes the corresponding in-situ-formed electrocatalyst,the 2D confinement effect of the layered structure,and the surface affinity based on Lewis acid-base interaction to improve the energy density of 2DSi-based LSB cells.Combined with the commercial carbon-based current collector,2DSi-based LSB cells achieve a volumetric energy density of 612 Wh Lcell^(−1) at 1 mA cm^(−2) with minor degradation of 0.17%per cycle,which rivals those of state-of-the-art LSBs.This study presents a method for the industrial production of high-energy-dense LSBs.展开更多
The widely accepted theory concerning the electrochemical energy storage mechanism of copper hexacyanoferrate(CuHCF)for supercapacitors is that CuHCF stores charge by the reversible redox processes of Fe^3+/Fe2+couple...The widely accepted theory concerning the electrochemical energy storage mechanism of copper hexacyanoferrate(CuHCF)for supercapacitors is that CuHCF stores charge by the reversible redox processes of Fe^3+/Fe2+couple and Cu cations are electrochemically inactive.In this work,CuHCF nanocubes(CuHCF-NC)were synthesized in the presence of potassium citrate and its electrochemical properties were tentatively studied in 1 mol/L Na2 SO4 aqueous electrolyte.Good supercapacitive performance was exhibited.The combined analyses of cyclic voltammogram(CV)and X-ray photoelectron spectroscopy(XPS)disclosed that the CuHCF nanocubes underwent the redox reactions of Fe^3+/Fe2+and Cu^2+/Cu+couples to store charges.The Cu^2+/Cu+redox couple was activated due to the strong coordination interaction between the carboxylate groups of citrate ions and surface Cu cations.展开更多
With the increasing demand for energy storage technology, iron-chromium flow batteries(ICFBs) have been widely concerned because of their price advantage. However, the low electrochemical activity of Cr^(3+)/Cr^(2+)re...With the increasing demand for energy storage technology, iron-chromium flow batteries(ICFBs) have been widely concerned because of their price advantage. However, the low electrochemical activity of Cr^(3+)/Cr^(2+)redox couples and the side hydrogen evolution reaction limit the industrial application of ICFBs. A multi-dimensional Bi/carbon composite electrocatalyst(Bi@C)for ICFB is designed and prepared to improve the electrochemical activity of Cr^(3+)/Cr^(2+)redox couples. Benefiting by using the Bimetal organic framework(Bi-MOF) with solid matrix as precursors, Bi nanospheres are highly dispersed on the Bi@C electrocatalyst that effectively enhances the electrochemical activity. The special morphology of Bi@C electrocatalyst helps the transfer of electrons and ions, significantly reducing the polarization of battery. Herein, the 3D porous carbon frames accelerate mass transfer, and the 2D carbon nanobelts and carbon layer coating on 0D Bi nanospheres improve the conductivity of Bi nanospheres. Therefore, the ICFB with multi-dimensional Bi@C electrocatalyst exhibits coulombic efficiency of 98.10% and energy efficiency of 79.14% at 140 m A cm^(-2), which is higher than ICFBs with commercial graphite carbon electrocatalyst and with heat treatment carbon felt. This work provides a simple and economical method to fabricate a high-performance multidimensional Bi@C electrocatalyst for Cr^(3+)/Cr^(2+)redox couples, boosting the development of ICFBs.展开更多
Natrium superionic conductor(NASICON)-type phosphates have aroused a great interest as cathode materials for sodium-ion batteries(SIBs)by virtue of their stable 3-dimensional frameworks,flexible molecular formula tuna...Natrium superionic conductor(NASICON)-type phosphates have aroused a great interest as cathode materials for sodium-ion batteries(SIBs)by virtue of their stable 3-dimensional frameworks,flexible molecular formula tunability,and superior ionic conductivity.Nevertheless,the intrinsic low electronic conductivity and relatively low theoretical specific capacity place obstacles in their way toward achieving higher electrochemical performance.In addition,only 2-electron reactions in most NASICON cathodes and poor reversibility of high-voltage redox couples severely limit their energy density.To address the above tough issues,an in-depth understanding of transition metal selection,elements ratio optimization,and Na-storage mechanism is of paramount importance.Here,this mini review summarizes the latest progresses on the NASICON-type phosphate cathodes for SIBs from the perspective of redox couple modulation.NASICON cathodes featuring high operating voltage and multielectron reactions are discussed in detail.Finally,the remaining challenges and personal outlooks based on redox couple regulation are put forward,shedding light on the designing rules for high-energy and long-durability NASICON-type phosphate cathodes for SIBs in the future.展开更多
Electrochemical cell can overcome the inherent intermittence of the renewable energy sources,thus showing great potentials in applications ranging from elec-trical energy storage to future smart grid.However,the curre...Electrochemical cell can overcome the inherent intermittence of the renewable energy sources,thus showing great potentials in applications ranging from elec-trical energy storage to future smart grid.However,the current electrochemical cells could not achieve the“total green”feature by fully utilizing the clean and abundant O_(2)/H_(2)O redox couples due to the enormous overpotentials for both oxygen reduction reaction(ORR)and oxygen release reaction(OER).Herein,we report a“total green”electrochemical composite film cell based on carbon dots(CDots),which can realize both ORR and OER in the acid environment.The in-air voltage generation(0.95 V,with a maximum power of 5.3μW)relies on the multiple-electron-transfer redox chemical reaction between the two active components inside the composite film,that is,ORR/OER of CDots and the redox reaction of polyaniline(PANI)on the electrode and the resulting proton concentration gradient.Interestingly,the cell can be self-recovered at low load,recharged by adding H_(2)O_(2),or electrocharged at high load.We anticipate that current study may open up new opportunities for designing and developing total-green energy storage and conversion systems for diverse applications.展开更多
The formation of inactive lithium(Li)in Li metal battery(LMB)primarily originates from the undesirable components of solid electrolyte interphase(SEI)and the growth of dendritic Li.LiNO_(3)has emerged as a promising e...The formation of inactive lithium(Li)in Li metal battery(LMB)primarily originates from the undesirable components of solid electrolyte interphase(SEI)and the growth of dendritic Li.LiNO_(3)has emerged as a promising electrolyte additive for mitigating interfacial instability and Li dendrite propagation through the in situ construction of nitride-rich SEI.However,the limited solubility of LiNO_(3)in carbonate electrolytes hinders its practical utilization.Herein,the bifunctional I^(-)-MgAl layered double hydroxide(LDH)is proposed to synergistically dissolve LiNO_(3)and rejuvenate inactive Li.The anion-exchange capability of LDH facilitates the substitution of native I^(-)with NO_(3)^(-),forming NO_(3)^(-)-MgAl LDH and simultaneously generating I_(3)^(-)/I^(-)redox mediators in electrolyte.This substitution not only achieves the dissolution of LiNO_(3),serving as a sustainable nitrogen source to optimize SEI components,but also enables the extracted I_(3)^(-)/I^(-)redox couple to react spontaneously with inactive Li,remarkably enhancing the coulombic efficiency.Consequently,the engineered electrolyte significantly extends the lifespan of Li||LiFePO4,Li||NCM,and Li@Cu||LiFePO4 cells.The unique architecture of LDH can precisely control the storage and release of NO_(3)^(-)and I^(-),offering a transformative electrolyte design framework for next-generation batteries by integrating two-dimensional material properties with electrochemical mechanisms.展开更多
Self-assembly of platinum nanoparticles were applied to fabrication of counter electrode for dye-sensitized solar cells on conductive oxide-coated glass substrate. The present Pt electrode exhibits high exchange curre...Self-assembly of platinum nanoparticles were applied to fabrication of counter electrode for dye-sensitized solar cells on conductive oxide-coated glass substrate. The present Pt electrode exhibits high exchange current density of 220 mA/cm2, which is comparable to those prepared by electrodeposition, magnetron sputtering or thermal decomposition of platinum chloride. After analysis by transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), it was found that the catalyst was structurally characterized as nanosized platinum metal clusters and was continuously arranged on electrode surface. The present nanostructure electrode had high electrocatalytic activity for the reduction of iodine in organic solution.展开更多
1 Results ITO-ZnTe/Chitosan-NH4I-I2/ITO photoelectrochemical solar cells have been fabricated and characterized by current-voltage characteristics.In this work,the ZnTe thin film was prepared by electrodeposition on i...1 Results ITO-ZnTe/Chitosan-NH4I-I2/ITO photoelectrochemical solar cells have been fabricated and characterized by current-voltage characteristics.In this work,the ZnTe thin film was prepared by electrodeposition on indium-tin-oxide coated glass.The chitosan electrolyte consists of NH4I salt and iodine.Iodine was added to provide the I3-/I- redox couple.The PEC solar cell was fabricated by sandwiching an electrolyte film between the ZnTe semiconductor and ITO conducting glass.The area of the solar cell...展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Ministry of Science and ICT(MSIT)(RS-2024-00344256 and RS-2025-02223634)。
文摘Lattice oxygen participation is crucial for oxygen-evolution reaction(OER)performance,but stabilizing the active high-valence cation remains a major challenge.This study focuses on iron oxyhydroxide(FeOOH),which exhibits a delicate balance between high-valence states and stability.A heterostructure(CeO_(2)/FeOOH)with an electron-rich,high-valence-state interface was synthesized via a simple co-precipitation method.Due to the work-function disparity between CeO_(2) and FeOOH,electron accumulation occurs in CeO_(2),while FeOOH attains a high-valence state.This enhanced valence state strengthens Fe–O covalency,facilitating lattice oxygen participation in oxygen-evolution reaction.Furthermore,electron-abundant CeO_(2) functions as a redox buffer,where the electron-reservable Ce3+/Ce4+redox couple stores excessive oxygen and donates electrons to stabilize high-valence FeOOH.By incorporating this“redox-buffering system,”Fe dissolution was minimized,significantly improving catalyst stability under harsh oxidizing conditions.The anion exchange membrane electrolyzer exhibited outstanding performance,delivering a current density of 500 mA cm^(-2) at 1.69 V,with remarkable stability over 100 h at 1 A cm^(-2).These findings provide a new strategy for stabilizing high-valence-state oxygen-evolution reaction catalysts,offering valuable insights for designing efficient and durable electrochemical systems.
基金support from the National Key Research and Development Program of China(No.2022YFB2502000)the National Natural Science Foundation of China(Grant Nos.52201277)+1 种基金the key program of the National Natural Science Foundation of China(Grant Nos.51831009)the National Outstanding Youth Foundation of China(No.52125104).
文摘Lithium and manganese-rich layered oxides(LMROs)have attracted extensive attention and are promising cathode materials for next-generation lithium ion batteries due to their high capacities and high energy densities.However,LMRO cathode suffers from severe capacity and voltage fading originating from irreversible surface oxygen evolution.Herein,we propose a facile redox couple strategy by introducing nitroxyl radicals species to regulate the surface anionic redox reaction of LMRO cathode.Differential electrochemical mass spectroscopy,X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses demonstrate that during charge process,the peroxide ion O_(2)^(2−)on the surface generated from the oxidation of lattice O^(2-)could be reduced back to stable O^(2-)by redox couple in time,thus avoiding oxygen evolution and structure degradation,as well as enhancing bulk oxygen redox activity.The enhanced LMRO electrode delivers a high capacity of 220.3 mAh g^(−1)at 1 C.An excellent cycling stability with a capacity retention of 94.4%is achieved after 500 cycles,as well as a suppressed voltage decay with only 1.12 mV per cycle.
基金supported by research grants from Innovative Research Group Project of National Natural Science Foundation of China(52021004)the National Key Research and Development Program of China(2022YFB3803300)+1 种基金the National Natural Science Foundation of China(62474026,62205140,and 12204071)the China Postdoctoral Science Foundation(2022M710532).
文摘Thermocells are attracting growing interest as a promising thermoelectric technology for low-grade heat harvesting.However,the scarcity of high-performance redox couples featuring intrinsically high thermopower(Se)and fast redox kinetics hinders the rapid development of thermocells.Identifying potential intrinsically high-performance redox couples remains a significant challenge.This work introduces a novel n-type copper(I/II)chloride(CuCl/CuCl2)redox couple with intrinsically high performance.Through tailored electrolyte design,long-term stability was significantly improved by reducing proton concentration to suppress cuprous ion photo-oxidation,while ammonium chloride solvation enhanced cuprous ion solubility.The resulting system achieves a Se value closely aligned with theoretical predictions and exhibits rapid redox kinetics.Consequently,the optimized CuCl/CuCl_(2) intrinsic system demonstrated a high S_(e) of 1.52 mV K^(−1) and a record-high normalized power density Pmax(ΔT)^(−2) of 0.399 mW m^(−2) K^(−2),surpassing previously reported intrinsic n-type thermocells and rivaling the performance of p-type pristine 0.4 M ferri/ferrocyanide systems.A prototype module comprising 30 p-n units successfully powered a line of light-emitting diodes or a thermohygrometer.This work introduces a valuable redox couple for further advancing high-performance thermocells and demonstrates a viable strategy for developing novel redox systems.
基金supported by the National Key Research and Development Program of China(No.2021YFB3500700)the National Natural Science Foundation of China(No.21976054)Fundamental Research Funds for the Central Universities(No.FRFTP-20-005A3)。
文摘Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)photocatalysts were successfully prepared via a simple in-situ doping method and exhibited superior PODS performance of dibenzothiophene(DBT)under mild reaction conditions.The 1.0 mol%Ce/MIL-125-NH_(2)catalyst achieved 100%sulfur removal within 22 min at 30℃ under visible light illumination,which is mainly attributed to the high surface area and the formation of Ce-Ti-oxo clusters due to electronic coupling.The valence transformation of Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators could not only expose abundant Lewis acid sites,but also promote the separation and transfer of photogenerated charges.In addition,increasing the reaction temperature has been demonstrated to be effective in promoting the PODS performance.Additionally,a thermo-enhanced PODS mechanism was proposed over Ce/MIL-125-NH_(2),demonstrating the great potential of thermal energy to promote the desulfurization activity.
基金the financial support from NSFC(21975027)NSFCMAECI(51861135202).
文摘Developing advanced secondary batteries with low cost and high safety has attracted increasing research interests across the world.In particular,the aqueous zinc-ion battery(AZIB)has been regarded as a promising candidate owing to the high abundance and capacity of Zn metal.Currently,manganese-based and vanadium-based oxides are most common choices for cathode materials used in AZIBs,but they unfortunately show a moderate cell voltage and limited rate performance induced by slow intercalation-extraction kinetics of Zn^(2+)ions.To address these issues,alternative cathode systems with tunable redox potentials and intrinsic fast kinetics have been exploited.In the past few years,conversion-type cathodes of I_(2)and S have become the most illustrative examples to match or even surpass the performance of conventional metal oxide cathodes in AZIBs.Herein,we sum up most recent progress in conversion-type cathodes and focus on novel ideas and concepts in designing/modifying cathodes for AZIBs with high voltage/capacity.Additionally,potential directions and future efforts are tentatively proposed for further development of conversion-type cathodes,aiming to speed up the practical application of AZIBs.
基金supported by the R&D Convergence Program of NST(National Research Council of Science&Technology)of the Republic of Korea(CAP-15-02-KBSI)a National Research Foundation of Korea(NRF)grant funded by the Korean Government(MSIT)(no.2019R1C1C1007745)a National Research Foundation of Korea(NRF)grant funded by the Korean Government(Ministry of Science,ICT&Future Planning)(no.2019R1A4A2001527).
文摘Lithium-sulfur batteries(LSBs)have emerged as promising power sources for high-performance devices such as electric vehicles.However,the poor energy density of LSBs owing to polysulfide shuttling and passivation has limited their further market penetration.To mitigate this challenge,two-dimensional(2D)siloxene(2DSi),a Si-based analog of graphene,is utilized as an additive for sulfur cathodes.The 2DSi is fabricated on a large scale by simple solvent extraction of calcium disilicide to form a thin-layered structure of Si planes functionalized with vertically aligned hydroxyl groups in the 2DSi.The stoichiometric reaction of 2DSi with polysulfides generates a thiosulfate redox mediator,secures the intercalation pathway,and reveals Lewis acidic sites within the siloxene galleries.The 2DSi utilizes the corresponding in-situ-formed electrocatalyst,the 2D confinement effect of the layered structure,and the surface affinity based on Lewis acid-base interaction to improve the energy density of 2DSi-based LSB cells.Combined with the commercial carbon-based current collector,2DSi-based LSB cells achieve a volumetric energy density of 612 Wh Lcell^(−1) at 1 mA cm^(−2) with minor degradation of 0.17%per cycle,which rivals those of state-of-the-art LSBs.This study presents a method for the industrial production of high-energy-dense LSBs.
基金supported by the National Natural Science Foundation of China(No.51877029)。
文摘The widely accepted theory concerning the electrochemical energy storage mechanism of copper hexacyanoferrate(CuHCF)for supercapacitors is that CuHCF stores charge by the reversible redox processes of Fe^3+/Fe2+couple and Cu cations are electrochemically inactive.In this work,CuHCF nanocubes(CuHCF-NC)were synthesized in the presence of potassium citrate and its electrochemical properties were tentatively studied in 1 mol/L Na2 SO4 aqueous electrolyte.Good supercapacitive performance was exhibited.The combined analyses of cyclic voltammogram(CV)and X-ray photoelectron spectroscopy(XPS)disclosed that the CuHCF nanocubes underwent the redox reactions of Fe^3+/Fe2+and Cu^2+/Cu+couples to store charges.The Cu^2+/Cu+redox couple was activated due to the strong coordination interaction between the carboxylate groups of citrate ions and surface Cu cations.
基金supported by the Industry-University-Research Cooperation project of Sinopec Dalian Petrochemical Research Institute (323038)the Fundamental Research Funds for the Central Universities (3132024625)the Young Technology Talents Fund of Dalian City (2022RQ027)。
文摘With the increasing demand for energy storage technology, iron-chromium flow batteries(ICFBs) have been widely concerned because of their price advantage. However, the low electrochemical activity of Cr^(3+)/Cr^(2+)redox couples and the side hydrogen evolution reaction limit the industrial application of ICFBs. A multi-dimensional Bi/carbon composite electrocatalyst(Bi@C)for ICFB is designed and prepared to improve the electrochemical activity of Cr^(3+)/Cr^(2+)redox couples. Benefiting by using the Bimetal organic framework(Bi-MOF) with solid matrix as precursors, Bi nanospheres are highly dispersed on the Bi@C electrocatalyst that effectively enhances the electrochemical activity. The special morphology of Bi@C electrocatalyst helps the transfer of electrons and ions, significantly reducing the polarization of battery. Herein, the 3D porous carbon frames accelerate mass transfer, and the 2D carbon nanobelts and carbon layer coating on 0D Bi nanospheres improve the conductivity of Bi nanospheres. Therefore, the ICFB with multi-dimensional Bi@C electrocatalyst exhibits coulombic efficiency of 98.10% and energy efficiency of 79.14% at 140 m A cm^(-2), which is higher than ICFBs with commercial graphite carbon electrocatalyst and with heat treatment carbon felt. This work provides a simple and economical method to fabricate a high-performance multidimensional Bi@C electrocatalyst for Cr^(3+)/Cr^(2+)redox couples, boosting the development of ICFBs.
基金financially supported by the National Natural Science Foundation of China(22075016 and 52372171)National Program for Support of Top-notch Young Professionals,Interdisciplinary Research Project for Young Teachers of USTB(FRF-IDRY-21-011)+2 种基金State Key Laboratory for Advanced Metals and Materials(2022Z-17)Fundamental Research Funds for the Central Universities(QNXM20220060)“Xiaomi Young Scholar”Funding Project,and 111 Project(B170003).
文摘Natrium superionic conductor(NASICON)-type phosphates have aroused a great interest as cathode materials for sodium-ion batteries(SIBs)by virtue of their stable 3-dimensional frameworks,flexible molecular formula tunability,and superior ionic conductivity.Nevertheless,the intrinsic low electronic conductivity and relatively low theoretical specific capacity place obstacles in their way toward achieving higher electrochemical performance.In addition,only 2-electron reactions in most NASICON cathodes and poor reversibility of high-voltage redox couples severely limit their energy density.To address the above tough issues,an in-depth understanding of transition metal selection,elements ratio optimization,and Na-storage mechanism is of paramount importance.Here,this mini review summarizes the latest progresses on the NASICON-type phosphate cathodes for SIBs from the perspective of redox couple modulation.NASICON cathodes featuring high operating voltage and multielectron reactions are discussed in detail.Finally,the remaining challenges and personal outlooks based on redox couple regulation are put forward,shedding light on the designing rules for high-energy and long-durability NASICON-type phosphate cathodes for SIBs in the future.
基金National Key Research and Development Program of China,Grant/Award Num-bers:2018YFE0306105,2020YFA0406104,2020YFA0406101National Natural Sci-ence Foundation of China,Grant/Award Numbers:21574094,51821002,51725204,21771132,51972216,52041202+4 种基金Natural Sci-ence Foundation of Jiangsu Province,Grant/Award Number:BK20190041Col-laborative Innovation Center of Suzhou Nano Science&Technology111 Project,Joint International Research Laboratory of Carbon-Based Functional Materials and Devicesthe Fund for Excellent Creative Research Teams of Jiangsu Higher Educa-tion InstitutionsJiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University。
文摘Electrochemical cell can overcome the inherent intermittence of the renewable energy sources,thus showing great potentials in applications ranging from elec-trical energy storage to future smart grid.However,the current electrochemical cells could not achieve the“total green”feature by fully utilizing the clean and abundant O_(2)/H_(2)O redox couples due to the enormous overpotentials for both oxygen reduction reaction(ORR)and oxygen release reaction(OER).Herein,we report a“total green”electrochemical composite film cell based on carbon dots(CDots),which can realize both ORR and OER in the acid environment.The in-air voltage generation(0.95 V,with a maximum power of 5.3μW)relies on the multiple-electron-transfer redox chemical reaction between the two active components inside the composite film,that is,ORR/OER of CDots and the redox reaction of polyaniline(PANI)on the electrode and the resulting proton concentration gradient.Interestingly,the cell can be self-recovered at low load,recharged by adding H_(2)O_(2),or electrocharged at high load.We anticipate that current study may open up new opportunities for designing and developing total-green energy storage and conversion systems for diverse applications.
基金supported by the National Natural Science Foundation of China(U20A20123,22379166,and 51874357)the Natural Science Foundation for Distinguished Young Scholars of Hunan Province(2022JJ10089)the Central South University Innovation-Driven Research Programme(2023CXQD034).
文摘The formation of inactive lithium(Li)in Li metal battery(LMB)primarily originates from the undesirable components of solid electrolyte interphase(SEI)and the growth of dendritic Li.LiNO_(3)has emerged as a promising electrolyte additive for mitigating interfacial instability and Li dendrite propagation through the in situ construction of nitride-rich SEI.However,the limited solubility of LiNO_(3)in carbonate electrolytes hinders its practical utilization.Herein,the bifunctional I^(-)-MgAl layered double hydroxide(LDH)is proposed to synergistically dissolve LiNO_(3)and rejuvenate inactive Li.The anion-exchange capability of LDH facilitates the substitution of native I^(-)with NO_(3)^(-),forming NO_(3)^(-)-MgAl LDH and simultaneously generating I_(3)^(-)/I^(-)redox mediators in electrolyte.This substitution not only achieves the dissolution of LiNO_(3),serving as a sustainable nitrogen source to optimize SEI components,but also enables the extracted I_(3)^(-)/I^(-)redox couple to react spontaneously with inactive Li,remarkably enhancing the coulombic efficiency.Consequently,the engineered electrolyte significantly extends the lifespan of Li||LiFePO4,Li||NCM,and Li@Cu||LiFePO4 cells.The unique architecture of LDH can precisely control the storage and release of NO_(3)^(-)and I^(-),offering a transformative electrolyte design framework for next-generation batteries by integrating two-dimensional material properties with electrochemical mechanisms.
基金Project supported by the National Research Fund for Fundamental Key Project (No. G2000028205) Innovative Foundation of Chinese Academy of Sciences and the National Natural Science Foundation of China (No. 29873057).
文摘Self-assembly of platinum nanoparticles were applied to fabrication of counter electrode for dye-sensitized solar cells on conductive oxide-coated glass substrate. The present Pt electrode exhibits high exchange current density of 220 mA/cm2, which is comparable to those prepared by electrodeposition, magnetron sputtering or thermal decomposition of platinum chloride. After analysis by transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), it was found that the catalyst was structurally characterized as nanosized platinum metal clusters and was continuously arranged on electrode surface. The present nanostructure electrode had high electrocatalytic activity for the reduction of iodine in organic solution.
文摘1 Results ITO-ZnTe/Chitosan-NH4I-I2/ITO photoelectrochemical solar cells have been fabricated and characterized by current-voltage characteristics.In this work,the ZnTe thin film was prepared by electrodeposition on indium-tin-oxide coated glass.The chitosan electrolyte consists of NH4I salt and iodine.Iodine was added to provide the I3-/I- redox couple.The PEC solar cell was fabricated by sandwiching an electrolyte film between the ZnTe semiconductor and ITO conducting glass.The area of the solar cell...
