Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structur...Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structural studies of other physicochemical properties are con-ducted on a series of materials obtained by the sol-gel method with different ratios of Gd and Sm cations.It is documented that changing the x value,and the resulting adjustment of the average ionic radius,have a significant impact on the crystal structure,stability,as well as on the total conductivity and thermomechanical properties of the materials,with the best results obtained for the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)composition.Oxygen electrodes are prepared using the selected compound,allowing to obtain low polarization resistance values,such as 0.086Ω·cm^(2)at 800℃.Systematic studies of electrocatalytic activity are conducted using La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(_(0.2))O_(3−δ)as the electrolyte for all electrodes,and Ce_(0.8)Gd_(0.2)O_(2−δ)electrolyte for the best performing Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes.The electrochemical data are analyzed using the distribution of relaxation times method.Also,the influence of the preparation method of the electrode material is in-ve`stigated using the electrospinning technique.Finally,the performance of the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes is tested in a Ni-YSZ(yttria-stabilized zirconia)anode-supported cell with a Ce_(0.8)Gd_(0.2)O_(2−δ)buffer layer,in the fuel cell and electrolyzer operating modes.With the electrospun electrode,a power density of 462 mW·cm^(−2)is obtained at 700℃,with a current density of ca.0.2 A·cm^(−2)at 1.3 V for the electrolysis at the same temperature,indicating better performance compared to the sol-gel-based electrode.展开更多
The proton ceramic electrochemical cell(PCEC),distinguished by its robust all-solid-state construction,emerges as a particularly promising contender in the realm of hydrogen production technologies.However,inadequate ...The proton ceramic electrochemical cell(PCEC),distinguished by its robust all-solid-state construction,emerges as a particularly promising contender in the realm of hydrogen production technologies.However,inadequate water-storage capability(hydration)and limited proton mobility within conventional PCEC oxygen electrodes hinder the efficiency of water splitting to oxygen,thereby restricting the broader application of PCECs.Here,we report a Ni-doped perovskite oxygen electrode Sr_(2)Fe_(1.4)Ni_(0.1)Mo_(1.5)O_(6-δ)(SFNM),where the incorporation of nickel can effectively amplify the concentration of oxygen vacancies while synergistically enhancing the hydration interaction between water molecules and the perovskite lattice.The enhanced hydration capacity facilitates proton-defect formation and lowers the energy barrier for proton migration.Benefiting from these synergistic enhancements,SFNM demonstrates a substantially reduced polarization resistance of approximately 0.078Ωcm^(2)at700℃under humidified conditions(pH_(2)O=0.1 atm).A PCEC utilizing the SFNM electrode achieves a remarkable current density of 2.60 A cm^(2)with an applied voltage of 1.3 V at 700℃.Furthermore,the PCEC exhibits favorable stability over a duration of 200 h.These outstanding results emphasize the potential of Ni doping to substantially improve both the hydration efficiency and proton mobility within perovskite electrode materials,positioning them as excellent candidates for high-performance PCECs.展开更多
Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction(ORR/OER),which are essential for the reversible protonic ceramic electroch...Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction(ORR/OER),which are essential for the reversible protonic ceramic electrochemical cell(R-PCEC)toward the sustainable hydrogen production and utilization.However,enhancement of their activity and stability remains challenging.Herein,we develop the Ta-regulated BaCo_(0.7)Fe_(0.3)O_(3-δ)perovskite oxygen electrode(Ba(Co_(0.7)Fe_(0.3))_(1-x)Ta_xO_(3-δ))with abundant oxygen defects and achieve the simultaneous enhancement in the electrocatalytic activity and stability toward ORR and OER.As-fabricated R-PCEC with(Ba(Co_(0.7)Fe_(0.3))_(0.9)Ta_(0.1)O_(3-δ))(BCFT10)oxygen electrode performs high power density of 1.47 W·cm^(-2)at 650℃in fuel cell mode,and the current density is up to-2.11 A·cm^(-2)at 1.4 V at 650℃in electrolysis mode,as well as the good stability in both the fuel cell and electrolysis modes.Importantly,the cell also demonstrates a stable cycling operation between fuel cell and electrolysis mode,suggesting a great potential of BCFT10 as oxygen electrode material for R-PCECs.展开更多
The hierarchically porous carbons （HPCs） were prepared by sol-gel selassembly technology in different surfactant concentrations and were used as the potential electrode for lithium oxygen batteries. The physical and...The hierarchically porous carbons （HPCs） were prepared by sol-gel selassembly technology in different surfactant concentrations and were used as the potential electrode for lithium oxygen batteries. The physical and electrochemical properties of the as-prepared HPCs were investigated by filed emission scanning electron microscopy （FE-SEM）, transmission electron microscopy （TEM）, nitrogen adsorption-desorption isotherm and galvanostatic charge/discharge. The results indicate that all of the HPCs mainly possess mesoporous structure with nearly similar pore size distribution. Using the HPCs as the electrode, a high discharge capacity for lithium oxygen battery can be achieved, and the discharge capacity increases with the specific surface area. Especially, the HPCs-3 oxygen electrode with CTAB concentration of 0.27 mol/L exhibits good capacity retention through controlling discharge depth to 800 mA·h/g and the highest discharge capacity of 2050 mA·h/g at a rate of 0.1 mA/cm2.展开更多
Oxygen electrocatalysis,exemplified by the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),is central to energy storage and conversion technologies such as fuel cells,metal-air batteries,and water ele...Oxygen electrocatalysis,exemplified by the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),is central to energy storage and conversion technologies such as fuel cells,metal-air batteries,and water electrolysis.However,highly effective and inexpensive earth-abundant materials are sought after to replace the noble metal-based electrocatalysts currently in use.Recently,metal-organic frameworks(MOFs)and carbon-based MOF derivatives have attracted considerable attention as efficient catalysts due to their exceedingly tunable morphologies,structures,compositions,and functionalization.Here,we report two-dimensional(2D)MOF/MOF derivative coupled arrays on nickel foam as binder-free bifunctional ORR/OER catalysts with enhanced electrocatalytic activity and stability.Their remarkable electrochemical properties are primarily attributed to fully exposed active sites and facilitated charge-transfer kinetics.The coupled and hierarchical nanosheet arrays produced via our growth-pyrolysis-regrowth strategy offer promise in the development of highly active electrodes for energy-related electrochemical devices.展开更多
To promote the electrocatalytic activity and stability of traditional(a_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)oxygen electrodes in reversible solid oxide cells(RSOCs),conventional physical mixed method was used t...To promote the electrocatalytic activity and stability of traditional(a_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)oxygen electrodes in reversible solid oxide cells(RSOCs),conventional physical mixed method was used to prepare the Pd-LSCF composite oxygen electrode.The cell with Pd-LSCF|GDC|YSZ|Ni-YSZ configuration shows perfect electrochemical performance in both solid oxide fuel cell(SOFC)mode and solid oxide electrolysis cell(SOEC)mode.In the SOFC mode,the cell achieves a power density of 1.73 W/cm^(2)at800℃higher than that of the LSCF oxygen electrode with 1.38 W/cm^(2).In the SOEC mode,the current density at 1.5 V is 1.67 A/cm^(2)at 800℃under 50 vol%steam concentration.Moreover,the reversibility and stability of the RSOCs were tested during 192 h long-term reversible operation.The degradation rate of the cell is only 2.2%/100 h and 2.5%/100 h in the SOEC and the SOFC modes,respectively.These results confirm that compositing Pd with the LSCF oxygen electrode can considerably boost the electrochemical performance of LSCF electrode in RSOCs field.展开更多
Transition metal oxide(TMO)nanoarrays are promising architecture designs for self-supporting oxygen electrodes to achieve high catalytic activities in lithium-oxygen(Li-O2)batteries.However,the poor conductive nature ...Transition metal oxide(TMO)nanoarrays are promising architecture designs for self-supporting oxygen electrodes to achieve high catalytic activities in lithium-oxygen(Li-O2)batteries.However,the poor conductive nature of TMOs and the confined growth of nanostructures on the limited surfaces of electrode substrates result in the low areal capacities of TMO nanoarray electrodes,which seriously deteriorates the intrinsically high energy densities of Li-O2 batteries.Herein,we propose a hybrid nanoarray architecture design that integrates the high electronic conductivity of carbon nanoflakes(CNFs)and the high catalytic activity of Co3 O4 nanosheets on carbon cloth(CC).Due to the synergistic effect of two differently featured components,the hybrid nanoarrays(Co3 O4-CNF@CC)achieve a high reversible capacity of3.14 mA h cm-2 that cannot be achieved by only single components.Further,CNFs grown on CC induce the three-dimensionally distributed growth of ultrafine Co3 O4 nanosheets to enable the efficient utilization of catalysts.Thus,with the high catalytic efficiency,hybrid Co3 O4-CNF@CC also achieves a more prolonged cycling life than pristine TMO nanoarrays.The present work provides a new strategy for improving the performance of nanoarray oxygen electrodes via the hybrid architecture design that integrates the intrinsic properties of each component and induces the three-dimensional distribution of catalysts.展开更多
Reversible protonic ceramic electrochemical cells(R-PCECs)are ideal,high-effi ciency devices that are environmentally friendly and have a modular design.This paper studies BaFe_(0.6)Zr_(0.1)Y_(0.3)O_(3−δ)(BFZY3)as a ...Reversible protonic ceramic electrochemical cells(R-PCECs)are ideal,high-effi ciency devices that are environmentally friendly and have a modular design.This paper studies BaFe_(0.6)Zr_(0.1)Y_(0.3)O_(3−δ)(BFZY3)as a cobalt-free perovskite oxygen electrode for high-performance R-PCECs where Y ions doping can increase the concentration of oxygen vacancies with a remarkable increase in catalytic performance.The cell with confi guration of Ni-BZCYYb/BZCYYb/BFZY3 demonstrated promising performance in dual modes of fuel cells(FCs)and electrolysis cells(ECs)at 650℃with low polarization resistance of 0.13Ωcm^(2),peak power density of 546.59 mW/cm^(2)in FC mode,and current density of−1.03 A/cm^(2)at 1.3 V in EC mode.The alternative operation between FC and EC modes for up to eight cycles with a total of 80 h suggests that the cell with BFZY3 is exceptionally stable and reversible over the long term.The results indicated that BFZY3 has considerable potential as an air electrode material for R-PCECs,permitting effi cient oxygen reduction and water splitting.展开更多
In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithiumoxygen batteries(Li-O2 batteries),most efforts currently focus on the design of rational porous architectures.Only...In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithiumoxygen batteries(Li-O2 batteries),most efforts currently focus on the design of rational porous architectures.Only few works study the surface chemistry effect that might be a critical factor influencing the capacities of carbonaceous electrodes.In addition,the surface chemistry effect is very difficult to be studied in composite electrodes due to the influences of binders and additives.Herein,we propose chemically activated carbon cloth(CACC) as an ideal model to investigate the effect of surface functional groups on the discharge capacities of carbonaceous oxygen electrodes for Li-O2 batteries.The intrinsic surface chemistry effect on the performance of carbonaceous cathode is directly observed for the first time without the influences of binders and additives.Results indicate that the surface carboxyl groups introduced by the chemical treatment not only function as the appropriate nucleation sites for Li2 O2 but also induce the formation of toroid-like Li2 O2.Thus,the surface carboxyl modification enhances the discharge capacities from 0.48 mAh/cm^2 of pristine carbon cloth to 1.23 mAh/cm^2 of CACC.This work presents an effective way to further optimize the carbonaceous oxygen electrodes via surface functional group engineering.展开更多
In recent years, the scale of use of fuel cells （FCs） has been increasing continuously. One of the essential elements that affect their work is a catalyst. Precious metals （mainly platinum） are known for their hig...In recent years, the scale of use of fuel cells （FCs） has been increasing continuously. One of the essential elements that affect their work is a catalyst. Precious metals （mainly platinum） are known for their high efficiency as FC catalysts. However, their high cost holds back the FCs from application on a large scale. Therefore, catalysts that do not contain precious metals are sought. Studies are focused mainly on the search for fuel electrode catalysts, but for the efficiency of FCs also the oxygen electrode catalyst is of great significance. The paper presents an analysis of the possibilitiesof using Ni-Co alloy as a catalyst for the oxygen electrode of the FC.展开更多
In recent years, as one of the most promising chemical power sources for future society, lithium–oxygen (Li–O2) battery receives great attention due to its extremely high theoretical energy density of 3505 Wh kg^(–...In recent years, as one of the most promising chemical power sources for future society, lithium–oxygen (Li–O2) battery receives great attention due to its extremely high theoretical energy density of 3505 Wh kg^(–1)[1–4]. In practice, large polarization and consequent low energy efficiency currently still hinder the application of Li–O2batteries, which mainly results from the sluggish electrochemical reaction kinetics of oxygen diffusion electrodes in aprotic electrolytes [5]. On one hand, oxygen reduction reaction (ORR)in aprotic electrolytes is intrinsically sluggish due to the difficult charge transfer, the low solubility of oxygen.展开更多
Reversible protonic ceramic electrochemical cells(RPCECs),which are capable of efficiently converting electrical and chemical energy in mutual directions,are considered highly promising alternatives for bidirectional ...Reversible protonic ceramic electrochemical cells(RPCECs),which are capable of efficiently converting electrical and chemical energy in mutual directions,are considered highly promising alternatives for bidirectional electrical energy generation or storage.However,the sluggish electrocatalytic activity at low temperatures and unsatisfactory operational durability of oxygen electrodes remain the primary challenges to the commercial application of R-PCECs.Here,the degradation mechanism of the BaFe_(0.4)Co_(0.4)Zr_(0.1)Y_(0.1)O_(3−δ)(BFCZY)oxygen electrode under humid conditions is systematically investigated.This degradation can be attributed to the formation of BaCO_(3)caused by water-facilitated Ba segregation.The activity and stability of the BFCZY oxygen electrode are significantly improved through heterointerface engineering by infiltrating the BaCO_(3)(BCO)catalyst.At 600°C in 30 vol%H_(2)O-air,heterointerface engineering decreases the polarization resistance of the BFCZY electrode by half(from 0.42 to 0.21Ω·cm^(2))and the decay rate by more than one order of magnitude(from 0.384 to 0.026Ω·cm^(2)/100 h).Moreover,an RPCEC with a BCO-BFCZY oxygen electrode exhibited high activity and stability in both fuel cell and water electrolysis modes.The substantially increased electrocatalytic activity and stability of the oxygen electrode are attributed primarily to the improved surface oxygen exchange process and inhibited Ba segregation.展开更多
The key ongoing challenge is to design and develop effective and inexpensive ox-ygenreductionreaction(ORR)catalysts toreplacePt-basedonesforcommercial use in fuel cells.Owing to its abundance and tunable electronic pr...The key ongoing challenge is to design and develop effective and inexpensive ox-ygenreductionreaction(ORR)catalysts toreplacePt-basedonesforcommercial use in fuel cells.Owing to its abundance and tunable electronic properties,in the cur-rent work,the synthesis of highly dispersed mixed valent copper oxide electro-catalyst is reported.The EC exhibits a high mass activity of 9.8 mA mg^(-1) and a high current density of 5.3 mA cm^(-2) in contrast to the benchmark(20 wt%)Pt/C catalyst in a 0.1-M KOH solution for ORR.The significantly high electrochemical activity at the cathode is believed to be due to the presence of the Cu(II)/Cu(I)redox pair.Furthermore,the catalyst has been shown to be highly stable,maintaining a high current retention of 78%for up to 24 h.Furthermore,the engineered material is also active for the oxygen evolution reaction,making it a viable replacement for con-ventional Pt/C in alkaline fuel cells.展开更多
Rechargeable Zn-air batteries(ZABs)have received extensive attention,while their real applications are highly restricted by the slow kinetics of the oxygen reduction and oxygen evolution reactions(ORR/OER).Herein,we r...Rechargeable Zn-air batteries(ZABs)have received extensive attention,while their real applications are highly restricted by the slow kinetics of the oxygen reduction and oxygen evolution reactions(ORR/OER).Herein,we report a“bridge”structured flexible self-supporting bifunctional oxygen electrode(CNT@Co-CNFF50-900)with strong active and stable Co-N/C@pyridine N/C@CNTs reaction centers.Benefiting from the electron distribution optimization and the advantages of hierarchical catalytic design,the CNT@Co-CNF_(F50-900)electrode had superior ORR/OER activity with a small potential gap(ΔE)of 0.74 V.Reinforced by highly graphitized carbon and the“π-π”bond,the free-standing CNT@Co-CNFF50-900 electrode exhibited outstanding catalytic stability with only 36 mV attenuation.Impressively,the CNT@Co-CNFF50-900-based liquid ZAB showed a high power density of 371 mW cm^(−2),a high energy density of 894 Wh kg^(−1),and a long cycling life of over 130 h.The assembled quasi-solid-state ZAB also demonstrated a high power density,attaining 81 mW cm^(−2),with excellent charge-discharge durability beyond 100 h and extremely high flexibility under the multi-angle application.This study provides an effective electrospinning solution for integrating high-efficiency electrocatalysts and electrodes for energy storage and conversion devices.展开更多
In this work,La_(2)NiO_(4+δ)-Ce_(0.55)La_(0.45)O_(2−δ)(denoted as LNO-xLDC)with various LDC contents(x=0,10,20,30,and 40 wt%)were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide c...In this work,La_(2)NiO_(4+δ)-Ce_(0.55)La_(0.45)O_(2−δ)(denoted as LNO-xLDC)with various LDC contents(x=0,10,20,30,and 40 wt%)were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide cells(RSOCs).Compared with the pure LNO,the optimum composition of LNO-30LDC exhibited the lowest polarization resistance(Rp)of 0.53 and 0.12Ω·cm^(2)in air at 650 and 750℃,respectively.The enhanced electrochemical performance of LNO-30LDC oxygen electrode was mainly attributed to the extended triple phase boundary and more oxygen ionic transfer channels.The hydrogen electrode supported single cell with LNO-30LDC oxygen electrode displayed peak power densities of 276,401,and 521 mW·cm^(−2)at 700,750,and 800℃,respectively.Moreover,the electrolysis current density of the single cell demonstrated 526.39 mA·cm^(−2) under 1.5 V at 800℃,and the corresponding hydrogen production rate was 220.03 mL·cm^(−2)·h^(−1).The encouraging results indicated that LNO-30LDC was a promising bifunctional oxygen electrode material for RSOCs.展开更多
Perovskite oxides based on the alkaline earth metal lanthanum for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in alkaline electrolytes are promising catalysts,but their catalytic activity and stabi...Perovskite oxides based on the alkaline earth metal lanthanum for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in alkaline electrolytes are promising catalysts,but their catalytic activity and stability remain unsatisfactory.Here,we synthesized a series of LaFe1-xMn2O3(x=0,0.1,0.3,0.5,0.7,0.9 and 1)perovskite oxides by doping Mn into LaFeO3(LF).The results show that the doping amount of Mn has a significant effect on the catalytic performance.When x=0.5,the catalyst LaFeo.sMno.sO3(LFM)exhibits the best performance.The limiting current density in 0.1 mol·L^-1 KOH solution is 7 mA·cm^-2,much larger than that of the commercial Pt/C catalyst(5.5 mA·cm^-2).Meanwhile,the performance of the doped catalyst is also superior to that of commercial Pt/C in terms of the long-term durability.The excellent catalytic performance of LFM may be ascribed to its abundant 0^2-/0^-species and low charge transfer resistance after doping the Mn element.展开更多
Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this...Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review.Various fabrication methods of these oxides are introduced in detail,and their advantages and disadvantages are analyzed.Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides.As a bifunctional electrocatalyst,perovskite-type oxides are widely used in rechargeable metal-air batteries.The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized.This work is concentrated on the structural stability,the phase compositions,and catalytic performance of perovskite-type oxides in oxygen/air electrodes.The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.展开更多
The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by ...The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by a simple method. The resulting device exhibited excellent electrocatalytic activities toward the oxygen reduction reaction. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements demonstrated that the porous morphology and uniformly dispersed Fe;C nanoparticles of the PCCM play an important role in the oxygen reduction reaction. A linear response range from 2mmol/L up to 110 mmol/L and a detection limit of 1.4 mmol/L was obtained with this sensor. The repeatability of the proposed sensor,evaluated in terms of relative standard deviation, was 3.0%. The successful fabrication of PCCM/GC electrode may promote the development of new porous carbon oxygen reduction reaction material for the oxygen reduction sensor.展开更多
Many non-precious metal-based catalysts with high intrinsic activity for catalytic reactions are prone to structural degradation in practical application,which leads to poor stability.In this work,we propose c-CoSe_(2...Many non-precious metal-based catalysts with high intrinsic activity for catalytic reactions are prone to structural degradation in practical application,which leads to poor stability.In this work,we propose c-CoSe_(2)/o-CoSe_(2)as the oxygen electrode of lithium-oxygen batteries(LOBs)to improve its cycle stability.The heterogeneous interface inside c-CoSe_(2)/o-CoSe_(2)leads to an increase in the covalence bonds between Co and Se ions,which greatly enhances the robustness of the crystal lattice,thereby improving the stability of the catalyst.In addition,the strong interaction between the mixed phases is favorable for adjusting the electron density around the active sites and boosting oxygen electrode kinetics.Moreover,the epitaxial growth of o-CoSe_(2)on c-CoSe_(2)will cause abundant heterogeneous interfaces and slight lattice distortion along the interfaces,thereby providing sufficient catalytic reaction sites.The DFT calculation results show that the optimized adsorption of intermediates at the heterogeneous interface plays an important role in boosting oxygen electrode reactions and improving the electrochemical performance of LOBs.The experimental results show that LOBs with the c-CoSe_(2)/o-CoSe_(2)electrodes exhibit outstanding performance,including large specific capacity of about 23,878 m A h g^(-1),high coulombic efficiency of up to 93.66%,and excellent stability of over 176 cycles(1410 h).展开更多
Protonic ceramic electrolysis cell(PCEC)is a promising technology for production of pure dry hydrogen due to the low operating temperature and high efficiency.One of the obstacles for commercialization of PCEC technol...Protonic ceramic electrolysis cell(PCEC)is a promising technology for production of pure dry hydrogen due to the low operating temperature and high efficiency.One of the obstacles for commercialization of PCEC technology is the poor performance and insufficient long-term durability of the oxygen electrode.In this study,we address the above challenge by designing a LaCoO_(3)(LC)catalyst infiltrated porous BaZr_(0.8)Y_(0.2)O_(3)−δ(BZY20)backbone electrode(LC-BZY20).The performance and durability of the LC-BZY20 electrode are investigated on symmetrical cells using electrochemical impedance spectroscopy(EIS).The total electrode polarization resistance(RP)values of the electrode are 0.56,1.24,2.18,and 2.90Ωcm2 in 3vol%humidified synthetic air at 600,550,500,and 450℃,respectively,indicating good electrochemical performance of the LC-BZY20 electrode.Furthermore,the LC-BZY20 electrode displays good stability,without significant performance degradation when tested at 600℃ in 10vol%humidified air for 900h.We further study the influence of oxygen partial pressure(PO_(2))and steam partial pressure(P_(H_(2)O))on the response of the EIS data,and propose a set of chemical and electrochemical processes involved in the steam splitting reaction in the LC-BZY20 electrode.展开更多
基金funded by the National Science Centre,Poland,on the basis of the decision number UMO-2020/37/B/ST8/02097supported by the program“Excellence Initiative-Research University”for the AGH University of Krakow(IDUB AGH,No.501.696.7996,Action 4,ID 9880).
文摘Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structural studies of other physicochemical properties are con-ducted on a series of materials obtained by the sol-gel method with different ratios of Gd and Sm cations.It is documented that changing the x value,and the resulting adjustment of the average ionic radius,have a significant impact on the crystal structure,stability,as well as on the total conductivity and thermomechanical properties of the materials,with the best results obtained for the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)composition.Oxygen electrodes are prepared using the selected compound,allowing to obtain low polarization resistance values,such as 0.086Ω·cm^(2)at 800℃.Systematic studies of electrocatalytic activity are conducted using La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(_(0.2))O_(3−δ)as the electrolyte for all electrodes,and Ce_(0.8)Gd_(0.2)O_(2−δ)electrolyte for the best performing Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes.The electrochemical data are analyzed using the distribution of relaxation times method.Also,the influence of the preparation method of the electrode material is in-ve`stigated using the electrospinning technique.Finally,the performance of the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes is tested in a Ni-YSZ(yttria-stabilized zirconia)anode-supported cell with a Ce_(0.8)Gd_(0.2)O_(2−δ)buffer layer,in the fuel cell and electrolyzer operating modes.With the electrospun electrode,a power density of 462 mW·cm^(−2)is obtained at 700℃,with a current density of ca.0.2 A·cm^(−2)at 1.3 V for the electrolysis at the same temperature,indicating better performance compared to the sol-gel-based electrode.
基金financially supported by the National Key R&D Program of China(No.2022YFB4002501)the National Natural Science Foundation of China(No.52202208)
文摘The proton ceramic electrochemical cell(PCEC),distinguished by its robust all-solid-state construction,emerges as a particularly promising contender in the realm of hydrogen production technologies.However,inadequate water-storage capability(hydration)and limited proton mobility within conventional PCEC oxygen electrodes hinder the efficiency of water splitting to oxygen,thereby restricting the broader application of PCECs.Here,we report a Ni-doped perovskite oxygen electrode Sr_(2)Fe_(1.4)Ni_(0.1)Mo_(1.5)O_(6-δ)(SFNM),where the incorporation of nickel can effectively amplify the concentration of oxygen vacancies while synergistically enhancing the hydration interaction between water molecules and the perovskite lattice.The enhanced hydration capacity facilitates proton-defect formation and lowers the energy barrier for proton migration.Benefiting from these synergistic enhancements,SFNM demonstrates a substantially reduced polarization resistance of approximately 0.078Ωcm^(2)at700℃under humidified conditions(pH_(2)O=0.1 atm).A PCEC utilizing the SFNM electrode achieves a remarkable current density of 2.60 A cm^(2)with an applied voltage of 1.3 V at 700℃.Furthermore,the PCEC exhibits favorable stability over a duration of 200 h.These outstanding results emphasize the potential of Ni doping to substantially improve both the hydration efficiency and proton mobility within perovskite electrode materials,positioning them as excellent candidates for high-performance PCECs.
基金financially supported by the National Key R&D Program of China(No.2022YFB4002201)the National Natural Science Foundation of China(Nos.52072362 and 52302119)+3 种基金Jilin Province Science and Technology Development Plan Funding Project(Nos.SKL202302039 and 20220201112GX)Jiangsu Province Innovation Support Program(No.BE2023092-2)Youth Innovation Promotion Association CAS(No.2021223)Open Funds of the State Key Laboratory of Rare Earth Resource Utilization(No.RERU2022008)。
文摘Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction(ORR/OER),which are essential for the reversible protonic ceramic electrochemical cell(R-PCEC)toward the sustainable hydrogen production and utilization.However,enhancement of their activity and stability remains challenging.Herein,we develop the Ta-regulated BaCo_(0.7)Fe_(0.3)O_(3-δ)perovskite oxygen electrode(Ba(Co_(0.7)Fe_(0.3))_(1-x)Ta_xO_(3-δ))with abundant oxygen defects and achieve the simultaneous enhancement in the electrocatalytic activity and stability toward ORR and OER.As-fabricated R-PCEC with(Ba(Co_(0.7)Fe_(0.3))_(0.9)Ta_(0.1)O_(3-δ))(BCFT10)oxygen electrode performs high power density of 1.47 W·cm^(-2)at 650℃in fuel cell mode,and the current density is up to-2.11 A·cm^(-2)at 1.4 V at 650℃in electrolysis mode,as well as the good stability in both the fuel cell and electrolysis modes.Importantly,the cell also demonstrates a stable cycling operation between fuel cell and electrolysis mode,suggesting a great potential of BCFT10 as oxygen electrode material for R-PCECs.
基金Projects (51272221,51072173,21203161) supported by the National Natural Science Foundation of ChinaProject (10CY005) supported by Industrial Project of Colleges and Universities of Hunan Province,China
文摘The hierarchically porous carbons （HPCs） were prepared by sol-gel selassembly technology in different surfactant concentrations and were used as the potential electrode for lithium oxygen batteries. The physical and electrochemical properties of the as-prepared HPCs were investigated by filed emission scanning electron microscopy （FE-SEM）, transmission electron microscopy （TEM）, nitrogen adsorption-desorption isotherm and galvanostatic charge/discharge. The results indicate that all of the HPCs mainly possess mesoporous structure with nearly similar pore size distribution. Using the HPCs as the electrode, a high discharge capacity for lithium oxygen battery can be achieved, and the discharge capacity increases with the specific surface area. Especially, the HPCs-3 oxygen electrode with CTAB concentration of 0.27 mol/L exhibits good capacity retention through controlling discharge depth to 800 mA·h/g and the highest discharge capacity of 2050 mA·h/g at a rate of 0.1 mA/cm2.
文摘Oxygen electrocatalysis,exemplified by the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),is central to energy storage and conversion technologies such as fuel cells,metal-air batteries,and water electrolysis.However,highly effective and inexpensive earth-abundant materials are sought after to replace the noble metal-based electrocatalysts currently in use.Recently,metal-organic frameworks(MOFs)and carbon-based MOF derivatives have attracted considerable attention as efficient catalysts due to their exceedingly tunable morphologies,structures,compositions,and functionalization.Here,we report two-dimensional(2D)MOF/MOF derivative coupled arrays on nickel foam as binder-free bifunctional ORR/OER catalysts with enhanced electrocatalytic activity and stability.Their remarkable electrochemical properties are primarily attributed to fully exposed active sites and facilitated charge-transfer kinetics.The coupled and hierarchical nanosheet arrays produced via our growth-pyrolysis-regrowth strategy offer promise in the development of highly active electrodes for energy-related electrochemical devices.
基金Project supported by the National Key Research&Development Project(2020YFB1506304)the National Natural Science Foundation of China(52172199,52072135,52002121)。
文摘To promote the electrocatalytic activity and stability of traditional(a_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)oxygen electrodes in reversible solid oxide cells(RSOCs),conventional physical mixed method was used to prepare the Pd-LSCF composite oxygen electrode.The cell with Pd-LSCF|GDC|YSZ|Ni-YSZ configuration shows perfect electrochemical performance in both solid oxide fuel cell(SOFC)mode and solid oxide electrolysis cell(SOEC)mode.In the SOFC mode,the cell achieves a power density of 1.73 W/cm^(2)at800℃higher than that of the LSCF oxygen electrode with 1.38 W/cm^(2).In the SOEC mode,the current density at 1.5 V is 1.67 A/cm^(2)at 800℃under 50 vol%steam concentration.Moreover,the reversibility and stability of the RSOCs were tested during 192 h long-term reversible operation.The degradation rate of the cell is only 2.2%/100 h and 2.5%/100 h in the SOEC and the SOFC modes,respectively.These results confirm that compositing Pd with the LSCF oxygen electrode can considerably boost the electrochemical performance of LSCF electrode in RSOCs field.
基金supported by grants from the National Natural Science Foundation of China(Nos.21673169,51672205,51972257)the National Key Research Program of China(No.2016YFA0202602)+1 种基金the Research Start-Up Fund from Wuhan University of Technologythe Fundamental Research Funds for the Central Universities(WUT:No.2019IB003)。
文摘Transition metal oxide(TMO)nanoarrays are promising architecture designs for self-supporting oxygen electrodes to achieve high catalytic activities in lithium-oxygen(Li-O2)batteries.However,the poor conductive nature of TMOs and the confined growth of nanostructures on the limited surfaces of electrode substrates result in the low areal capacities of TMO nanoarray electrodes,which seriously deteriorates the intrinsically high energy densities of Li-O2 batteries.Herein,we propose a hybrid nanoarray architecture design that integrates the high electronic conductivity of carbon nanoflakes(CNFs)and the high catalytic activity of Co3 O4 nanosheets on carbon cloth(CC).Due to the synergistic effect of two differently featured components,the hybrid nanoarrays(Co3 O4-CNF@CC)achieve a high reversible capacity of3.14 mA h cm-2 that cannot be achieved by only single components.Further,CNFs grown on CC induce the three-dimensionally distributed growth of ultrafine Co3 O4 nanosheets to enable the efficient utilization of catalysts.Thus,with the high catalytic efficiency,hybrid Co3 O4-CNF@CC also achieves a more prolonged cycling life than pristine TMO nanoarrays.The present work provides a new strategy for improving the performance of nanoarray oxygen electrodes via the hybrid architecture design that integrates the intrinsic properties of each component and induces the three-dimensional distribution of catalysts.
基金support from the National Key Research&Development Project(2022YFB4002201)National Natural Science Foundation of China(Nos.52172199,52072135,52002121)+1 种基金Hubei Province(2023BAB115)Jiangsu Province(BZ2022027).
文摘Reversible protonic ceramic electrochemical cells(R-PCECs)are ideal,high-effi ciency devices that are environmentally friendly and have a modular design.This paper studies BaFe_(0.6)Zr_(0.1)Y_(0.3)O_(3−δ)(BFZY3)as a cobalt-free perovskite oxygen electrode for high-performance R-PCECs where Y ions doping can increase the concentration of oxygen vacancies with a remarkable increase in catalytic performance.The cell with confi guration of Ni-BZCYYb/BZCYYb/BFZY3 demonstrated promising performance in dual modes of fuel cells(FCs)and electrolysis cells(ECs)at 650℃with low polarization resistance of 0.13Ωcm^(2),peak power density of 546.59 mW/cm^(2)in FC mode,and current density of−1.03 A/cm^(2)at 1.3 V in EC mode.The alternative operation between FC and EC modes for up to eight cycles with a total of 80 h suggests that the cell with BFZY3 is exceptionally stable and reversible over the long term.The results indicated that BFZY3 has considerable potential as an air electrode material for R-PCECs,permitting effi cient oxygen reduction and water splitting.
基金supported by grants from the National Natural Science Foundation of China (Nos.21673169,51672205)the National Key R&D Program of China (No.2016YFA0202602)+1 种基金the Research Start-Up Fund from Wuhan University of Technologythe Fundamental Research Funds for the Central Universities (WUT:Nos.2019IB003,2016IVA083)
文摘In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithiumoxygen batteries(Li-O2 batteries),most efforts currently focus on the design of rational porous architectures.Only few works study the surface chemistry effect that might be a critical factor influencing the capacities of carbonaceous electrodes.In addition,the surface chemistry effect is very difficult to be studied in composite electrodes due to the influences of binders and additives.Herein,we propose chemically activated carbon cloth(CACC) as an ideal model to investigate the effect of surface functional groups on the discharge capacities of carbonaceous oxygen electrodes for Li-O2 batteries.The intrinsic surface chemistry effect on the performance of carbonaceous cathode is directly observed for the first time without the influences of binders and additives.Results indicate that the surface carboxyl groups introduced by the chemical treatment not only function as the appropriate nucleation sites for Li2 O2 but also induce the formation of toroid-like Li2 O2.Thus,the surface carboxyl modification enhances the discharge capacities from 0.48 mAh/cm^2 of pristine carbon cloth to 1.23 mAh/cm^2 of CACC.This work presents an effective way to further optimize the carbonaceous oxygen electrodes via surface functional group engineering.
文摘In recent years, the scale of use of fuel cells （FCs） has been increasing continuously. One of the essential elements that affect their work is a catalyst. Precious metals （mainly platinum） are known for their high efficiency as FC catalysts. However, their high cost holds back the FCs from application on a large scale. Therefore, catalysts that do not contain precious metals are sought. Studies are focused mainly on the search for fuel electrode catalysts, but for the efficiency of FCs also the oxygen electrode catalyst is of great significance. The paper presents an analysis of the possibilitiesof using Ni-Co alloy as a catalyst for the oxygen electrode of the FC.
基金supported by grants from the National Natural Science Foundation of China (Nos. 21673169, 51672205, 51972257)the National Key Research Program of China (No. 2016YFA0202602)+1 种基金the Research Start-Up Fund from Wuhan University of Technologythe Fundamental Research Funds for the Central Universities (WUT: No. 2019IB003)。
文摘In recent years, as one of the most promising chemical power sources for future society, lithium–oxygen (Li–O2) battery receives great attention due to its extremely high theoretical energy density of 3505 Wh kg^(–1)[1–4]. In practice, large polarization and consequent low energy efficiency currently still hinder the application of Li–O2batteries, which mainly results from the sluggish electrochemical reaction kinetics of oxygen diffusion electrodes in aprotic electrolytes [5]. On one hand, oxygen reduction reaction (ORR)in aprotic electrolytes is intrinsically sluggish due to the difficult charge transfer, the low solubility of oxygen.
基金the National Key R&D Program of China(No.2021YFB4001502)is highly appreciated。
文摘Reversible protonic ceramic electrochemical cells(RPCECs),which are capable of efficiently converting electrical and chemical energy in mutual directions,are considered highly promising alternatives for bidirectional electrical energy generation or storage.However,the sluggish electrocatalytic activity at low temperatures and unsatisfactory operational durability of oxygen electrodes remain the primary challenges to the commercial application of R-PCECs.Here,the degradation mechanism of the BaFe_(0.4)Co_(0.4)Zr_(0.1)Y_(0.1)O_(3−δ)(BFCZY)oxygen electrode under humid conditions is systematically investigated.This degradation can be attributed to the formation of BaCO_(3)caused by water-facilitated Ba segregation.The activity and stability of the BFCZY oxygen electrode are significantly improved through heterointerface engineering by infiltrating the BaCO_(3)(BCO)catalyst.At 600°C in 30 vol%H_(2)O-air,heterointerface engineering decreases the polarization resistance of the BFCZY electrode by half(from 0.42 to 0.21Ω·cm^(2))and the decay rate by more than one order of magnitude(from 0.384 to 0.026Ω·cm^(2)/100 h).Moreover,an RPCEC with a BCO-BFCZY oxygen electrode exhibited high activity and stability in both fuel cell and water electrolysis modes.The substantially increased electrocatalytic activity and stability of the oxygen electrode are attributed primarily to the improved surface oxygen exchange process and inhibited Ba segregation.
文摘The key ongoing challenge is to design and develop effective and inexpensive ox-ygenreductionreaction(ORR)catalysts toreplacePt-basedonesforcommercial use in fuel cells.Owing to its abundance and tunable electronic properties,in the cur-rent work,the synthesis of highly dispersed mixed valent copper oxide electro-catalyst is reported.The EC exhibits a high mass activity of 9.8 mA mg^(-1) and a high current density of 5.3 mA cm^(-2) in contrast to the benchmark(20 wt%)Pt/C catalyst in a 0.1-M KOH solution for ORR.The significantly high electrochemical activity at the cathode is believed to be due to the presence of the Cu(II)/Cu(I)redox pair.Furthermore,the catalyst has been shown to be highly stable,maintaining a high current retention of 78%for up to 24 h.Furthermore,the engineered material is also active for the oxygen evolution reaction,making it a viable replacement for con-ventional Pt/C in alkaline fuel cells.
基金supported by the National Key Research and Development Program of China(2022YFE0138900)National Natural Science Foundation of China(21972017)+2 种基金the Fundamental Research Funds for the Central Universities(2232022D-18,CUSF-DH-T-2023061)Shanghai Sailing Program(22YF1400700)the Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(22CGA37).
文摘Rechargeable Zn-air batteries(ZABs)have received extensive attention,while their real applications are highly restricted by the slow kinetics of the oxygen reduction and oxygen evolution reactions(ORR/OER).Herein,we report a“bridge”structured flexible self-supporting bifunctional oxygen electrode(CNT@Co-CNFF50-900)with strong active and stable Co-N/C@pyridine N/C@CNTs reaction centers.Benefiting from the electron distribution optimization and the advantages of hierarchical catalytic design,the CNT@Co-CNF_(F50-900)electrode had superior ORR/OER activity with a small potential gap(ΔE)of 0.74 V.Reinforced by highly graphitized carbon and the“π-π”bond,the free-standing CNT@Co-CNFF50-900 electrode exhibited outstanding catalytic stability with only 36 mV attenuation.Impressively,the CNT@Co-CNFF50-900-based liquid ZAB showed a high power density of 371 mW cm^(−2),a high energy density of 894 Wh kg^(−1),and a long cycling life of over 130 h.The assembled quasi-solid-state ZAB also demonstrated a high power density,attaining 81 mW cm^(−2),with excellent charge-discharge durability beyond 100 h and extremely high flexibility under the multi-angle application.This study provides an effective electrospinning solution for integrating high-efficiency electrocatalysts and electrodes for energy storage and conversion devices.
基金Science and Technology Project of Jiangxi Provincial Education Department(GJJ190734)The National Natural Science Foundation of China(51962015)。
文摘In this work,La_(2)NiO_(4+δ)-Ce_(0.55)La_(0.45)O_(2−δ)(denoted as LNO-xLDC)with various LDC contents(x=0,10,20,30,and 40 wt%)were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide cells(RSOCs).Compared with the pure LNO,the optimum composition of LNO-30LDC exhibited the lowest polarization resistance(Rp)of 0.53 and 0.12Ω·cm^(2)in air at 650 and 750℃,respectively.The enhanced electrochemical performance of LNO-30LDC oxygen electrode was mainly attributed to the extended triple phase boundary and more oxygen ionic transfer channels.The hydrogen electrode supported single cell with LNO-30LDC oxygen electrode displayed peak power densities of 276,401,and 521 mW·cm^(−2)at 700,750,and 800℃,respectively.Moreover,the electrolysis current density of the single cell demonstrated 526.39 mA·cm^(−2) under 1.5 V at 800℃,and the corresponding hydrogen production rate was 220.03 mL·cm^(−2)·h^(−1).The encouraging results indicated that LNO-30LDC was a promising bifunctional oxygen electrode material for RSOCs.
基金supported by the National Natural Science Foundation of China(Grants Nos.91745112,21604051,21671133 and 21507081)the Science and Technology Commission of Shanghai Municipality(Grant Nos.19DZ2271100,18020500800 and 18JC1412900).
文摘Perovskite oxides based on the alkaline earth metal lanthanum for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in alkaline electrolytes are promising catalysts,but their catalytic activity and stability remain unsatisfactory.Here,we synthesized a series of LaFe1-xMn2O3(x=0,0.1,0.3,0.5,0.7,0.9 and 1)perovskite oxides by doping Mn into LaFeO3(LF).The results show that the doping amount of Mn has a significant effect on the catalytic performance.When x=0.5,the catalyst LaFeo.sMno.sO3(LFM)exhibits the best performance.The limiting current density in 0.1 mol·L^-1 KOH solution is 7 mA·cm^-2,much larger than that of the commercial Pt/C catalyst(5.5 mA·cm^-2).Meanwhile,the performance of the doped catalyst is also superior to that of commercial Pt/C in terms of the long-term durability.The excellent catalytic performance of LFM may be ascribed to its abundant 0^2-/0^-species and low charge transfer resistance after doping the Mn element.
基金Projects(51504212,21573184,51703061)supported by the National Natural Science Foundation of ChinaProject(2018J01521)supported by the Natural Science Foundation of Fujian Province,ChinaProject(fma2017202)supported by the Open Fund of Fujian Provincial Key Laboratory of Functional Materials and Applications(Xiamen University of Technology),China
文摘Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review.Various fabrication methods of these oxides are introduced in detail,and their advantages and disadvantages are analyzed.Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides.As a bifunctional electrocatalyst,perovskite-type oxides are widely used in rechargeable metal-air batteries.The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized.This work is concentrated on the structural stability,the phase compositions,and catalytic performance of perovskite-type oxides in oxygen/air electrodes.The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.
基金the National Natural Science Foundation of China (No.21273097)the project from the State Key Laboratory of Electroanalytical Chemistry (No.2013)the Science Foundation of Jilin Province (No.20130204003GX)
文摘The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by a simple method. The resulting device exhibited excellent electrocatalytic activities toward the oxygen reduction reaction. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements demonstrated that the porous morphology and uniformly dispersed Fe;C nanoparticles of the PCCM play an important role in the oxygen reduction reaction. A linear response range from 2mmol/L up to 110 mmol/L and a detection limit of 1.4 mmol/L was obtained with this sensor. The repeatability of the proposed sensor,evaluated in terms of relative standard deviation, was 3.0%. The successful fabrication of PCCM/GC electrode may promote the development of new porous carbon oxygen reduction reaction material for the oxygen reduction sensor.
基金financially supported by the National Natural Science Foundation of China(No.21905033)Department of Science and Technology of Sichuan Province(No.2019YJ0503)State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(No.2020P4FZG02A)。
文摘Many non-precious metal-based catalysts with high intrinsic activity for catalytic reactions are prone to structural degradation in practical application,which leads to poor stability.In this work,we propose c-CoSe_(2)/o-CoSe_(2)as the oxygen electrode of lithium-oxygen batteries(LOBs)to improve its cycle stability.The heterogeneous interface inside c-CoSe_(2)/o-CoSe_(2)leads to an increase in the covalence bonds between Co and Se ions,which greatly enhances the robustness of the crystal lattice,thereby improving the stability of the catalyst.In addition,the strong interaction between the mixed phases is favorable for adjusting the electron density around the active sites and boosting oxygen electrode kinetics.Moreover,the epitaxial growth of o-CoSe_(2)on c-CoSe_(2)will cause abundant heterogeneous interfaces and slight lattice distortion along the interfaces,thereby providing sufficient catalytic reaction sites.The DFT calculation results show that the optimized adsorption of intermediates at the heterogeneous interface plays an important role in boosting oxygen electrode reactions and improving the electrochemical performance of LOBs.The experimental results show that LOBs with the c-CoSe_(2)/o-CoSe_(2)electrodes exhibit outstanding performance,including large specific capacity of about 23,878 m A h g^(-1),high coulombic efficiency of up to 93.66%,and excellent stability of over 176 cycles(1410 h).
基金support from the China Scholarship Council(CSC201807040049)from DTU Energy.The authors would like to thank H.Henriksen for his help with cell testing.
文摘Protonic ceramic electrolysis cell(PCEC)is a promising technology for production of pure dry hydrogen due to the low operating temperature and high efficiency.One of the obstacles for commercialization of PCEC technology is the poor performance and insufficient long-term durability of the oxygen electrode.In this study,we address the above challenge by designing a LaCoO_(3)(LC)catalyst infiltrated porous BaZr_(0.8)Y_(0.2)O_(3)−δ(BZY20)backbone electrode(LC-BZY20).The performance and durability of the LC-BZY20 electrode are investigated on symmetrical cells using electrochemical impedance spectroscopy(EIS).The total electrode polarization resistance(RP)values of the electrode are 0.56,1.24,2.18,and 2.90Ωcm2 in 3vol%humidified synthetic air at 600,550,500,and 450℃,respectively,indicating good electrochemical performance of the LC-BZY20 electrode.Furthermore,the LC-BZY20 electrode displays good stability,without significant performance degradation when tested at 600℃ in 10vol%humidified air for 900h.We further study the influence of oxygen partial pressure(PO_(2))and steam partial pressure(P_(H_(2)O))on the response of the EIS data,and propose a set of chemical and electrochemical processes involved in the steam splitting reaction in the LC-BZY20 electrode.
