The Li-CO_(2)battery has been highly rated as an intriguing technique for balancing the carbon cycle for years,but it is still significantly challenged by the obstacles such as limited reversibility,sluggish kinetics,...The Li-CO_(2)battery has been highly rated as an intriguing technique for balancing the carbon cycle for years,but it is still significantly challenged by the obstacles such as limited reversibility,sluggish kinetics,and poor energy efficiency.Hence,the design and development of advance catalysts that can enhance the kinetics and reversibility of the CO_(2)electrochemical cycling reactions are considered the imperative tasks.Transition metal-based catalysts are widely considered appealing owing to their unfilled dorbitals,rich and adjustable valences,as well as processibility.In this review,the working mechanism and the key issues of the CO_(2)electrochemical cycling reaction are discussed first.Then the strategies for composition and structure design of different type of transition metal-based catalysts are highlighted,including their benefits,limitations,and the ways to implement these strategies.Finally,based on the pioneering research,the perspectives on the challenges and key points for the future development of cathode catalyst are proposed.展开更多
Highly active cathode catalysts for efficient formation/decomposition of Li_(2)O_(2)are essential for the performance improvement of lithium-oxygen batteries(LOBs).In this study,a grain-refining Co_(0.85)Se catalyst w...Highly active cathode catalysts for efficient formation/decomposition of Li_(2)O_(2)are essential for the performance improvement of lithium-oxygen batteries(LOBs).In this study,a grain-refining Co_(0.85)Se catalyst with a lattice spacing of 2.69 A of(101)plane closely matching with the(100)plane(2.72A)of Li_(2)O_(2)was applied for high-performance LOBs.Highly(101)plane exposed Co_(0.85)Se@CNT was synthesized by a simple one-pot hydrothermal method.The Co_(0.85)Se with the lattice matching effect not only led to the efficient conversion and polarized growth of Li_(2)O_(2),but also prevented the formation of byproducts.Density functional theory(DFT)calculations reveal that Co_(0.85)Se(101)plane has the intrinsic catalytic ability to generate/decompose Li_(2)O_(2)during ORR/OER process,due to its homogeneous electron distribution,suitable adsorption energy,and promoted Li_(2)O_(2)growth kinetics.As a consequence,the(101)plane highly exposed Co_(0.85)Se@CNT-80 electrode exhibited remarkable cycle stability over 2400 h at 100 mA/g and 290cycles at 500 mA/g,which is about 2 times longer than other electrodes.展开更多
Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the e...Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the electrochemical properties of lithium–oxygen batteries(LOBs), especially the cycling performance, a high-efficiency cathode catalyst is the most important component.Hence, we aim to demonstrate that CuCr_2O_4@rGO(CCO@rGO) nanocomposites, which are synthesized using a facile hydrothermal method and followed by a series of calcination processes, are an effective cathode catalyst. The obtained CCO@rGO nanocomposites which served as the cathode catalyst of the LOBs exhibited an outstanding cycling performance for over 100 cycles with a fixed capacity of 1000 mAh g^(-1) at a current density of 200 mA g^(-1). The enhanced properties were attributed to the synergistic effect between the high catalytic efficiency of the spinel-structured CCO nanoparticles, the high specific surface area, and high conductivity of the rGO.展开更多
An amorphous CoSnO3@rGO nanocomposite fabricated using a surfactant‐assisted assembly method combined with thermal treatment served as a catalyst for non‐aqueous lithium‐oxygen(Li‐O2)batteries.In contrast to the s...An amorphous CoSnO3@rGO nanocomposite fabricated using a surfactant‐assisted assembly method combined with thermal treatment served as a catalyst for non‐aqueous lithium‐oxygen(Li‐O2)batteries.In contrast to the specific surface area of the bare CoSnO3 nanoboxes(104.3 m2 g–1),the specific surface area of the CoSnO3@rGO nanocomposite increased to approximately 195.8 m2 g–1 and the electronic conductivity also improved.The increased specific surface area provided more space for the deposition of Li2O2,while the improved electronic conductivity accelerated the decomposition of Li2O2.Compared to bare CoSnO3,the overpotential reduced by approximately 20 and 60 mV at current densities of 100 and 500 mA g?1 when CoSnO3@rGO was used as the catalyst.A Li‐O2 battery using a CoSnO3@rGO nanocomposite as the cathode catalyst cycled indicated a superior cyclic stability of approximately 130 cycles at a current density of 200 mA g–1 with a limited capacity of 1000 mAh g–1,which is 25 cycles more than that of the bare amorphous CoSnO3 nanoboxes.展开更多
Microbial fuel cells(MFCs)have a simple structure and excellent pollutant treatment and power generation performance.However,the slow kinetics of the oxygen reduction reaction(ORR)at the MFC cathode limit power genera...Microbial fuel cells(MFCs)have a simple structure and excellent pollutant treatment and power generation performance.However,the slow kinetics of the oxygen reduction reaction(ORR)at the MFC cathode limit power generation.The electrochemical performance of MFCs can be improved through electrocatalysis.Thus far,metal-based catalysts have shown astonishing results in the field of electrocatalysis,enabling MFC devices to demonstrate power generation capabilities comparable to those of Pt,thus showing enormous potential.This article reviews the research progress of meta-based MFC cathode ORR catalysts,including the ORR reaction mechanism of MFC,different types of catalysts,and preparation strategies.The catalytic effects of different catalysts in MFC are compared and summarized.Before discussing the practical application and expanded manufacturing of catalysts,we summarize the key challenges that must be addressed when using metal-based catalysts in MFC,with the aim of providing a scientific direction for the future development of advanced materials.展开更多
In this work,a composite of 3D network nitrogen-doped porous carbon on reduced graphene oxide(denoted as NPC/rGO)was derived from pyrolysis of zeolitic imidazolate framework-8 and graphene oxide.The as-prepared NPC/rG...In this work,a composite of 3D network nitrogen-doped porous carbon on reduced graphene oxide(denoted as NPC/rGO)was derived from pyrolysis of zeolitic imidazolate framework-8 and graphene oxide.The as-prepared NPC/rGO possesses high specific surface area,nitrogen doping and mesopores.When evaluated as the cathode catalyst for Li–O_(2)batteries,NPC/rGO exhibited higher specific capacity,better cyclability,and greater rate capability than either nitrogen doped porous carbon or reduced graphene oxide.The outstanding performances suggest that zeolitic imidazolate framework derived nitrogen doped porous carbon materials are promising for Li–O_(2)batteries.展开更多
Developing cathode catalyst layers(CCL)with efficient mass transport capability is crucial to developing ultra-low Pt loading(<50μg·cm^(-2))proton exchange membrane fuel cells(PEMFCs).Herein,CCLs with various...Developing cathode catalyst layers(CCL)with efficient mass transport capability is crucial to developing ultra-low Pt loading(<50μg·cm^(-2))proton exchange membrane fuel cells(PEMFCs).Herein,CCLs with various pore distributions were constructed by depositing Pt onto the integrated carbonaceous films consisting of carbon nanoparticles(CNs),three-dimensional(3D)graphene nanosheets(GNs),and nanocomposites of CNs and GNs(CNs-GNs),respectively.The hierarchical mesoporous pore distributions of CCLs strongly affect the effective exposure of Pt active sites,proton-transfer resistance,and oxygen mass transport efficiencies related to Knudsen diffusion and local resistance at the Pt/ionomer interface.The CCL with Pt/CNs-GNs(50.0μgPt·cm^(-2))features a unique tri-modal pore distribution concentrated at 10.2,20.4,and 43.7 nm,providing efficient three-phase boundaries with a significantly higher active surface area of 49.67 m2·g^(-1),lower oxygen transport resistance and proton resistance of down to 18.68 s·m^(-1) and 0.0603Ω·cm^(2),compared with Pt/CNs(31.48 m^(2)·g^(-1),41.17 s·m^(-1),and 0.0702Ω·cm^(2))with a single-modal pore distribution at 9.5 nm and Pt/GNs(38.21 m^(2)·g^(-1),33.40 s·m^(-1),and 0.0654Ω·cm^(2))with a bi-modal pore distribution at 9.8 and 20.9 nm.Correspondingly,the cell with Pt/CNs-GNs delivers a high power output of up to 1.01 W·cm^(-2) and presents a high durability that satisfies the 2025 targets set by the U.S.Department of Energy.This work provides new insights into the critical role of hierarchically mesoporous pore distribution of CCL for constructing high-performance PEMFCs with ultra-low Pt loading<50μg·cm^(-2).展开更多
Appropriate hydrophobicity and porosity of the proton-exchange membrane fuel cell(PEMFC)cathode catalyst layer(CCL)are essential for efficient charge and mass transport.In this study,the effects of the CCL hydrophobic...Appropriate hydrophobicity and porosity of the proton-exchange membrane fuel cell(PEMFC)cathode catalyst layer(CCL)are essential for efficient charge and mass transport.In this study,the effects of the CCL hydrophobicity and porosity on PEMFC performance were comprehensively investigated.Compared to a normal CCL,a cathode hydrophobic duallayer catalyst structure(with a 2:1 Pt loading ratio between the inner and outer layers and 9.3%polytetrafluoroethylene(PTFE)in the outer layer)exhibited a 29.8%increase in power density.Among the tested pore-forming agents,ammonium bicarbonate(NH_4HCO_(3))was the most suitable because of its low pyrolysis temperature.The maximum power density of the CCL with a porous structure(prepared with a Pt/C:NH_4HCO_(3)mass ratio of 1:3)was 38.3%higher than that of the normal CCL.By simultaneously optimizing the pore structure and hydrophobicity of the CCL,the maximum power density of the cathode hydrophobic dual-layer CCL(DCL)with pores showed a 44.7%increase compared to that of the normal CCL.This study demonstrates for the first time that simultaneously optimizing cathode porosity and hydrophobicity can enhance PEMFC performance.展开更多
Developing excellent cathode catalysts with superior catalytic activities is essential for the practical application of aprotic lithium-oxygen batteries(LOBs).Herein,we successfully synthesized nitrogen-doped hollow m...Developing excellent cathode catalysts with superior catalytic activities is essential for the practical application of aprotic lithium-oxygen batteries(LOBs).Herein,we successfully synthesized nitrogen-doped hollow mesoporous carbon spheres encapsulated with molybdenum disulfide(MoS_(2))nanosheets as the cathode catalyst for rechargeable LOBs,and the relationship between the battery performance and structural characteristics was intensively researched.We found that the synergistic effect of the nitrogen-doped mesoporous carbon and MoS_(2)nanosheets endows superior electrocatalytic activities to the composite catalyst.On the one hand,the nitrogen-doped mesoporous carbon could enable fast charge transfer and effectively accommodate more discharging products in the composite skeleton.On the other hand,the thin MoS_(2)nanosheets could promote mass transportation to facilitate the revisable formation and decomposition of the Li2O2 during oxygen reduction reaction and oxygen evolution reaction,and the side reactions were also prevented,apparently due to their full coverage on the composite surfaces.As a result,the catalytic cathode loaded with 2H-MoS_(2)-modified nitrogen-doped hollow mesoporous carbon spheres exhibited excellent electrochemical performance in terms of large discharge-/charge-specific capacities with low overpotentials and extended cycling life,and they hold great promise for acting as the cathode catalyst for high-performance LOBs.展开更多
High cost has undoubtedly become the biggest obstacle to the commercialization of proton exchange membrane fuel cells(PEMFCs),in which Pt-based catalysts employed in the cathodic catalyst layer(CCL)account for the maj...High cost has undoubtedly become the biggest obstacle to the commercialization of proton exchange membrane fuel cells(PEMFCs),in which Pt-based catalysts employed in the cathodic catalyst layer(CCL)account for the major portion of the cost.Although nonprecious metal catalysts(NPMCs)show appreciable activity and stability in the oxygen reduction reaction(ORR),the performance of fuel cells based on NPMCs remains unsatisfactory compared to those using Pt-based CCL.Therefore,most studies on NPMC-based fuel cells focus on developing highly active catalysts rather than facilitating oxygen transport.In this work,the oxygen transport behavior in CCLs based on highly active Fe-N-C catalysts is comprehensively explored through the elaborate design of two types of membrane electrode structures,one containing low-Pt-based CCL and NPMCbased dummy catalyst layer(DCL)and the other containing only the NPMC-based CCL.Using Zn-N-C based DCLs of different thickness,the bulk oxygen transport resistance at the unit thickness in NPMC-based CCL was quantified via the limiting current method combined with linear fitting analysis.Then,the local and bulk resistances in NPMC-based CCLs were quantified via the limiting current method and scanning electron microscopy,respectively.Results show that the ratios of local and bulk oxygen transport resistances in NPMCbased CCL are 80%and 20%,respectively,and that an enhancement of local oxygen transport is critical to greatly improve the performance of NPMC-based PEMFCs.Furthermore,the activity of active sites per unit in NPMCbased CCLs was determined to be lower than that in the Pt-based CCL,thus explaining worse cell performance of NPMC-based membrane electrode assemblys(MEAs).It is believed that the development of NPMC-based PEMFCs should proceed not only through the design of catalysts with higher activity but also through the improvement of oxygen transport in the CCL.展开更多
In order to advance the commercialization of rechargeable Li-air batteries,it is of importance to explore cathode catalyst with efficient catalytic activity.Transition metal oxides have poor electrical conductivity,wh...In order to advance the commercialization of rechargeable Li-air batteries,it is of importance to explore cathode catalyst with efficient catalytic activity.Transition metal oxides have poor electrical conductivity,while cobalt phosphide has excellent electrical conductivity and large specific surface area.Nevertheless,its application in organic Li-air batteries has been much less studied,and the electrocatalytic activity desires to be further elevated.Here,CoP/Co_(2)P heterojunction composite with higher polarity was fabricated.The discharge product of high-polarity CoP/Co_(2)P had a new porous box-like morphology,which was easy to be decomposed and exposed more active sites.The highly polar CoP/Co_(2)P heterostructure composite had homogeneous pores,the synergistic effect existed between CoP and Co_(2)P,and the discharge product was porous box mixed with Li_(2)O_(2)and LiOH,which made CoP/Co_(2)P achieve high specific capacity of14632 m Ah/g and cycle stably 161 times when used as air electrode cathode catalyst.This work furnished a thought for the construction of cathode catalysts with efficient catalytic activity for Li-air batteries.展开更多
Noble metals, such as platinum, ruthenium and iridium‐group metals, are often used as oxygen reduction or evolution reaction （ORR/OER） electrocatalysts. To reduce the cost and provide an application of bifunctional...Noble metals, such as platinum, ruthenium and iridium‐group metals, are often used as oxygen reduction or evolution reaction （ORR/OER） electrocatalysts. To reduce the cost and provide an application of bifunctional catalysis, in this work, cobalt oxide supported on nitrogen and phospho‐rus co‐doped carbon （Co3O4/NPC） was fabricated and examined as a bifunctional electrocatalyst for OER and ORR. To prepare Co3O4/NPC, NPC was pyrolyzed from melamine and phytic acid support‐ed on carbon, followed by the solvothermal synthesis of Co3O4 on NPC. Linear sweep voltammetry was used to evaluate the activity for OER and ORR. For OER, Co3O4/NPC showed an onset potential of 0.54 V （versus the saturated calomel electrode） and a current density of 21.95 mA/cm2 at 0.80 V, which was better than both Co3O4/C and NPC. The high activity of Co3O4/NPC was attributed to a synergistic effect of the N, P co‐dopants and Co3O4. For ORR, Co3O4/NPC exhibited an activity close to commercial Pt/C in terms of the diffusion limited current density （–4.49 vs–4.76 mA/cm2 at–0.80 V）, and Co3O4 played the key role for the catalysis. Chronoamperometry （current versus time） was used to evaluate the stability, which showed that Co3O4/NPC maintained 46%current after the chronoamperometry test for OER and 95% current for ORR. Overall, Co3O4/NPC exhibited high activity and improved stability for both OER and ORR.展开更多
Combining nanomaterials with complementary properties in a well-designed structure is an effective tactic to exploit multifunctional, high-performance materials for the energy conversion and storage. Nonprecious metal...Combining nanomaterials with complementary properties in a well-designed structure is an effective tactic to exploit multifunctional, high-performance materials for the energy conversion and storage. Nonprecious metal catalysts, such as cobalt oxide, with superior activity and excellent stability to other catalysts are widely desired. Nevertheless, the performance of CoO nanoparticles as an electrode material were significantly limit for its inferior conductivity, dissolution, and high cohesion. Herein, we grow ultrafine cobalt monoxide to decorate the interlayer and surface of the Ti3C2 Txnanosheets via a hydrothermal method companied by calcination. The layered MXenes act as the underlying conductive substrate,which not only increase the electron transfer rate at the interface but also greatly improve the electrochemical properties of the nanosized Co O particles by restricting the aggregation of CoO. The resulting CoO/Ti3C2 Txnanomaterial is applied as oxygen electrode for lithium-oxygen battery and achieves more than 160 cycles and first cycle capacity of 16,220 mAh g-1 at 100 mA g-1. This work paves a promising avenue for constructing a bi-functional catalyst by coupling the active component of a transition metal oxide(TMO) with the MXene materials in lithium-oxygen battery.展开更多
Li-O_(2) batteries(LOBs) have been perceived as the most potential clean energy system for fast-growing electric vehicles by reason of their environmentally friendlier,high energy density and high reversibility.Howeve...Li-O_(2) batteries(LOBs) have been perceived as the most potential clean energy system for fast-growing electric vehicles by reason of their environmentally friendlier,high energy density and high reversibility.However,there are still some issues limiting the practical application of LOBs,such as the large gap between the actual capacity level and the theoretical capacity,low rate performance as well as short cycle life.Herein,hollow CeO_(2)/Co_(3)O_(4) polyhedrons have been synthesized by MOF template with a simple method.And it is was further served as a cathode catalyst in Li-O_(2) batteries.By means of the synergistic effect of two different transition metal oxides,nano-sized hollow porous CeO_(2)/Co_(3)O_(4) cathode obtained better capacity and cycle performance.As a result,excellent cyclability of exceeding 140 and 90 cycles are achieved at a fixed capacity of 600 and 1000 mAh/g,respectively.The successful application of this catalyst in LOBs offers a novel route in the aspect of the synthesis of other hollow porous composite oxides as catalysts for cathodes in LOBs systems by the MOF template method.展开更多
Na-CO_(2) batteries have attracted extensive attention due to their high theoretical energy density(1125 Wh/kg),efficient utilization of CO_(2),and abundant sodium resources.However,they are trapped by the sluggish de...Na-CO_(2) batteries have attracted extensive attention due to their high theoretical energy density(1125 Wh/kg),efficient utilization of CO_(2),and abundant sodium resources.However,they are trapped by the sluggish decomposition kinetic of discharge products (mainly Na_(2)CO_(3)) on cathode side during the charging process.Here we prepared a series of nano-composites composed of RuO_(2) nanoparticles in situ loaded on activated multi-walled carbon nanotubes (RuO_(2)@a-MWCNTs) through hydrolyzing reaction followed by calcination method and used them as cathode catalysts to accelerate the decomposition of Na_(2)CO_(3).Among all catalysts,the RuO_(2)@a-MWCNTs with appropriate ratio of RuO_(2)(49.7 wt%) demonstrated best stability and rate performance in Na-CO_(2) batteries,benefiting from both high specific surface area (160.3 m^(2)/g) and highly dispersed RuO_(2) with ultrafine nanostructures (~2 nm).At a limited capacity of 500 mAh/g,Na-CO_(2) batteries could afford the operation of over 120 cycles at 100 mA/g,and even at the current density to 500 mA/g,the charge voltage was still lower than 4.0 V after 40 cycles.Further theoretical calculations proved that RuO_(2) was the catalytically active center and contributed to the decomposition of Na_(2)CO_(3) by weakening the C=O bond.The synergetic functions of high specific surface(CNTs) and high catalytic activity (RuO_(2)) will inspire more progress on metal-CO_(2) batteries.展开更多
Proton exchange membrane fuel cells(PEMFCs) are regarded as a promising sustainable energy conversion technology due to their environmental friendliness and high efficiency [1,2]. However, the sluggish kinetics of fou...Proton exchange membrane fuel cells(PEMFCs) are regarded as a promising sustainable energy conversion technology due to their environmental friendliness and high efficiency [1,2]. However, the sluggish kinetics of four-electron oxygen reduction reaction(ORR) result in the cathode catalysts requiring more than five times the amount of precious metal Pt compared to the anode, which limits the widespread application of PEMFCs.展开更多
To tackle the issues of high cost,low durability and poor resistance to chemical poisoning of Pt-based materials as cathode catalysts for an oxygen reduction reaction(ORR),an effective method is to design and synthesi...To tackle the issues of high cost,low durability and poor resistance to chemical poisoning of Pt-based materials as cathode catalysts for an oxygen reduction reaction(ORR),an effective method is to design and synthesize heteroatom doped carbon materials,regarded as promising electrocatalysts to replace Ptbased counterparts,due to their low cost,high stability and anti-poisoning ability.The potential of N,B co-doping has been proved by theoretical calculations,and there are still great challenges in the synthesis of such materials.Here,we employ a facile approach to obtain a N,B co-doped carbon material.The resulting material pyrolysed at 1000°C(NBC-1000)shows excellent ORR activity,exceeding that of the same type of catalysts reported so far.Not only is the NBC-1000 electrocatalyst comparable to the commercial Pt/C in terms of the onset potential,half-wave potential,diffusion limiting current density and electron transfer number,but also it has better durability and methanol tolerance than Pt/C.展开更多
2D MXene nanosheets are regarded as promising cathode catalysts towards the hydrogen evolution reaction (HER), while their overall electrocatalytic ability still needs to be optimized before the practical application....2D MXene nanosheets are regarded as promising cathode catalysts towards the hydrogen evolution reaction (HER), while their overall electrocatalytic ability still needs to be optimized before the practical application. In this contribution, we put forward a controllable assembly approach for constructing a heterostructured nanoarchitecture made from ultrafine MoS_(2) quantum dot-decorated Ti_(3)C_(2)T_(x) MXene nanosheets (MQDs/Ti_(3)C_(2)T_(x)). Benefiting from the remarkable structural features of the ultrathin catalyst layers, homogeneous MoS_(2) distribution, optimized electronic structure, and good electron conductivity, the resulting MQD/Ti_(3)C_(2)T_(x) catalyst exhibits superior HER properties with a low onset potential of 66 mV, a small Tafel slope of 74 mV dec^(-1), and a long lifespan, in contrast to the insufficient HER ability for bare MoS_(2) quantum dots and Ti_(3)C_(2)T_(x) itself. DFT calculations further disclose the optimized band structure of the MQDs/Ti_(3)C_(2)T_(x) model with numerous diverse active sites, which play fundamental roles in boosting the HER kinetics.展开更多
Rational design and synthesis of cathode catalysts are crucial for enhancing the performance of rechargeable Li-O_(2) batteries.Here,we report a controlled synthesis of the nanocomposite,Co_(3)O_(4) nanohorns coated w...Rational design and synthesis of cathode catalysts are crucial for enhancing the performance of rechargeable Li-O_(2) batteries.Here,we report a controlled synthesis of the nanocomposite,Co_(3)O_(4) nanohorns coated with MnO_(2) nanosheets on a Ni foam(Co_(3)O_(4)@MnO_(2)/Ni).It integrates the catalytic activities of oxygen reduction and oxygen evolution reactions and functions as a carbon-and binder-free cathode catalyst for rechargeable Li-O_(2) batteries.This nanocomposite catalyst presents a small discharge/charge voltage gap of 0.76 V(a low polarization)and a long cycle life of 170 cycles at 300 mA g^(-1),coupled with an ionic liquid-based electrolyte,0.5 M lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide(EMITFSI),which are much better than those based on the individual Co_(3)O_(4) and MnO_(2) cathodes.The enhanced electrochemical performance is ascribed to the integrated bifunctional catalytic activities and the porous micro/nanostructure of the Co_(3)O_(4)@MnO_(2)/Ni nanocomposite,as well as the ionic liquid-based electrolyte,indicating its promising application in rechargeable Li-O_(2) batteries.展开更多
The stability of cathode catalyst layers(CCLs)in proton exchange membrane fuel cells(PEMFCs)is critically undermined by Pt dissolution and the loss of effective gas-water management associated with carbon support corr...The stability of cathode catalyst layers(CCLs)in proton exchange membrane fuel cells(PEMFCs)is critically undermined by Pt dissolution and the loss of effective gas-water management associated with carbon support corrosion.In this work,we develop a porous TiN nanotube-supported Pt(i.e.,Pt/TiN NTs)CCL that integrates robust Pt-Ti interfacial bonding with a highly accessible nanotube network to address these persistent challenges.The formation of abundant Pt-Ti bonds at the interface markedly strengthens Pt anchoring,resulting in a 2.3-fold reduction in Pt dissolution and minimal particle coarsening after accelerated durability testing compared to nanoflows-based controls dominated by Pt-N-Ti interactions.The membrane electrode assembly fabricated with this CCL achieves a peak power density of 0.81 W/cm^(2) and demonstrates exceptional durability,retaining 77%of its initial mass activity and 87.3%of its power density following aggressive square-wave potential cycling,meeting the 2025 U.S.Department of Energy benchmarks.Computational fluid dynamics simulation further reveal that the unique porous architecture facilitates efficient oxygen transport and rapid water removal,sustaining high catalytic utilization under operational conditions.This strategy establishes TiN NTs scaffolds as a generalizable solution for the next generation of carbon-free,high-stability catalyst layers,offering practical guidance for durable and efficient fuel cell design.展开更多
基金financially supported by the National Natural Science Foundation of China(52201254,52234001,52074177)the National Key Research and Development Program(2022YFC3900905)+3 种基金the Natural Science Foundation of Shandong Province(ZR2020QE012,ZR2020MB090,ZR2023ME155,ZR2023ME085)the Scientific Research Foundation for New Talents in University of Jinan(XRC2406)the project of “20 Items of University”of Jinan(202228046)the Introducing Major Universities and Research Institutions to Jointly Build Innovative Carrier Project of Jining City(2023DYDS022)。
文摘The Li-CO_(2)battery has been highly rated as an intriguing technique for balancing the carbon cycle for years,but it is still significantly challenged by the obstacles such as limited reversibility,sluggish kinetics,and poor energy efficiency.Hence,the design and development of advance catalysts that can enhance the kinetics and reversibility of the CO_(2)electrochemical cycling reactions are considered the imperative tasks.Transition metal-based catalysts are widely considered appealing owing to their unfilled dorbitals,rich and adjustable valences,as well as processibility.In this review,the working mechanism and the key issues of the CO_(2)electrochemical cycling reaction are discussed first.Then the strategies for composition and structure design of different type of transition metal-based catalysts are highlighted,including their benefits,limitations,and the ways to implement these strategies.Finally,based on the pioneering research,the perspectives on the challenges and key points for the future development of cathode catalyst are proposed.
基金supported by National Natural Science Foundation of China(Nos.52173286,52207249)Major basic research project of Natural Science Foundation of Shandong Province(No.ZR2023ZD12)+1 种基金the State Key Laboratory of Marine Resource Utilization in South China Sea(Hainan University)(No.MRUKF2023013)Open Program of Guangxi Key Laboratory of Information Materials(No.221024-K)。
文摘Highly active cathode catalysts for efficient formation/decomposition of Li_(2)O_(2)are essential for the performance improvement of lithium-oxygen batteries(LOBs).In this study,a grain-refining Co_(0.85)Se catalyst with a lattice spacing of 2.69 A of(101)plane closely matching with the(100)plane(2.72A)of Li_(2)O_(2)was applied for high-performance LOBs.Highly(101)plane exposed Co_(0.85)Se@CNT was synthesized by a simple one-pot hydrothermal method.The Co_(0.85)Se with the lattice matching effect not only led to the efficient conversion and polarized growth of Li_(2)O_(2),but also prevented the formation of byproducts.Density functional theory(DFT)calculations reveal that Co_(0.85)Se(101)plane has the intrinsic catalytic ability to generate/decompose Li_(2)O_(2)during ORR/OER process,due to its homogeneous electron distribution,suitable adsorption energy,and promoted Li_(2)O_(2)growth kinetics.As a consequence,the(101)plane highly exposed Co_(0.85)Se@CNT-80 electrode exhibited remarkable cycle stability over 2400 h at 100 mA/g and 290cycles at 500 mA/g,which is about 2 times longer than other electrodes.
基金jointly supported by National Science Foundation of China (Grant Numbers: 11572271 and 51302236)the Principal Fund of Xiamen University (Hosted by Guanghui Yue, 2018)
文摘Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the electrochemical properties of lithium–oxygen batteries(LOBs), especially the cycling performance, a high-efficiency cathode catalyst is the most important component.Hence, we aim to demonstrate that CuCr_2O_4@rGO(CCO@rGO) nanocomposites, which are synthesized using a facile hydrothermal method and followed by a series of calcination processes, are an effective cathode catalyst. The obtained CCO@rGO nanocomposites which served as the cathode catalyst of the LOBs exhibited an outstanding cycling performance for over 100 cycles with a fixed capacity of 1000 mAh g^(-1) at a current density of 200 mA g^(-1). The enhanced properties were attributed to the synergistic effect between the high catalytic efficiency of the spinel-structured CCO nanoparticles, the high specific surface area, and high conductivity of the rGO.
基金supported by the National Natural Science Foundation of China (11405144)the Fundamental Research Funds for the Central Universities (20720180081)~~
文摘An amorphous CoSnO3@rGO nanocomposite fabricated using a surfactant‐assisted assembly method combined with thermal treatment served as a catalyst for non‐aqueous lithium‐oxygen(Li‐O2)batteries.In contrast to the specific surface area of the bare CoSnO3 nanoboxes(104.3 m2 g–1),the specific surface area of the CoSnO3@rGO nanocomposite increased to approximately 195.8 m2 g–1 and the electronic conductivity also improved.The increased specific surface area provided more space for the deposition of Li2O2,while the improved electronic conductivity accelerated the decomposition of Li2O2.Compared to bare CoSnO3,the overpotential reduced by approximately 20 and 60 mV at current densities of 100 and 500 mA g?1 when CoSnO3@rGO was used as the catalyst.A Li‐O2 battery using a CoSnO3@rGO nanocomposite as the cathode catalyst cycled indicated a superior cyclic stability of approximately 130 cycles at a current density of 200 mA g–1 with a limited capacity of 1000 mAh g–1,which is 25 cycles more than that of the bare amorphous CoSnO3 nanoboxes.
基金supported by the National Natural Science Foundation of China(Nos.52170019 and 51973015)the Fundamental Research Funds for the Central Universities(No.06500100)the“Ten thousand plan”-National High-level Personnel of Special Support Program.National Environmental and Energy Science and Technology International Cooperation Base.
文摘Microbial fuel cells(MFCs)have a simple structure and excellent pollutant treatment and power generation performance.However,the slow kinetics of the oxygen reduction reaction(ORR)at the MFC cathode limit power generation.The electrochemical performance of MFCs can be improved through electrocatalysis.Thus far,metal-based catalysts have shown astonishing results in the field of electrocatalysis,enabling MFC devices to demonstrate power generation capabilities comparable to those of Pt,thus showing enormous potential.This article reviews the research progress of meta-based MFC cathode ORR catalysts,including the ORR reaction mechanism of MFC,different types of catalysts,and preparation strategies.The catalytic effects of different catalysts in MFC are compared and summarized.Before discussing the practical application and expanded manufacturing of catalysts,we summarize the key challenges that must be addressed when using metal-based catalysts in MFC,with the aim of providing a scientific direction for the future development of advanced materials.
基金supported by NSFC(21421001)the Tianjin Municipal Science and Technology Commission(16PTSYJC00010 and 17JCQNJC06400)the Open Funding of the State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology,Zhejiang University of Technology(GCTKF2014001)in China.
文摘In this work,a composite of 3D network nitrogen-doped porous carbon on reduced graphene oxide(denoted as NPC/rGO)was derived from pyrolysis of zeolitic imidazolate framework-8 and graphene oxide.The as-prepared NPC/rGO possesses high specific surface area,nitrogen doping and mesopores.When evaluated as the cathode catalyst for Li–O_(2)batteries,NPC/rGO exhibited higher specific capacity,better cyclability,and greater rate capability than either nitrogen doped porous carbon or reduced graphene oxide.The outstanding performances suggest that zeolitic imidazolate framework derived nitrogen doped porous carbon materials are promising for Li–O_(2)batteries.
基金supported by the National Natural Science Foundation of China(No.22379031)the Guangxi Science and Technology Project of China(No.AB16380030)。
文摘Developing cathode catalyst layers(CCL)with efficient mass transport capability is crucial to developing ultra-low Pt loading(<50μg·cm^(-2))proton exchange membrane fuel cells(PEMFCs).Herein,CCLs with various pore distributions were constructed by depositing Pt onto the integrated carbonaceous films consisting of carbon nanoparticles(CNs),three-dimensional(3D)graphene nanosheets(GNs),and nanocomposites of CNs and GNs(CNs-GNs),respectively.The hierarchical mesoporous pore distributions of CCLs strongly affect the effective exposure of Pt active sites,proton-transfer resistance,and oxygen mass transport efficiencies related to Knudsen diffusion and local resistance at the Pt/ionomer interface.The CCL with Pt/CNs-GNs(50.0μgPt·cm^(-2))features a unique tri-modal pore distribution concentrated at 10.2,20.4,and 43.7 nm,providing efficient three-phase boundaries with a significantly higher active surface area of 49.67 m2·g^(-1),lower oxygen transport resistance and proton resistance of down to 18.68 s·m^(-1) and 0.0603Ω·cm^(2),compared with Pt/CNs(31.48 m^(2)·g^(-1),41.17 s·m^(-1),and 0.0702Ω·cm^(2))with a single-modal pore distribution at 9.5 nm and Pt/GNs(38.21 m^(2)·g^(-1),33.40 s·m^(-1),and 0.0654Ω·cm^(2))with a bi-modal pore distribution at 9.8 and 20.9 nm.Correspondingly,the cell with Pt/CNs-GNs delivers a high power output of up to 1.01 W·cm^(-2) and presents a high durability that satisfies the 2025 targets set by the U.S.Department of Energy.This work provides new insights into the critical role of hierarchically mesoporous pore distribution of CCL for constructing high-performance PEMFCs with ultra-low Pt loading<50μg·cm^(-2).
基金supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(Grant No.52488201)the National Key R&D Program of China(Grant No.2021YFF0500504)the Fundamental Research Funds for the Central Universities。
文摘Appropriate hydrophobicity and porosity of the proton-exchange membrane fuel cell(PEMFC)cathode catalyst layer(CCL)are essential for efficient charge and mass transport.In this study,the effects of the CCL hydrophobicity and porosity on PEMFC performance were comprehensively investigated.Compared to a normal CCL,a cathode hydrophobic duallayer catalyst structure(with a 2:1 Pt loading ratio between the inner and outer layers and 9.3%polytetrafluoroethylene(PTFE)in the outer layer)exhibited a 29.8%increase in power density.Among the tested pore-forming agents,ammonium bicarbonate(NH_4HCO_(3))was the most suitable because of its low pyrolysis temperature.The maximum power density of the CCL with a porous structure(prepared with a Pt/C:NH_4HCO_(3)mass ratio of 1:3)was 38.3%higher than that of the normal CCL.By simultaneously optimizing the pore structure and hydrophobicity of the CCL,the maximum power density of the cathode hydrophobic dual-layer CCL(DCL)with pores showed a 44.7%increase compared to that of the normal CCL.This study demonstrates for the first time that simultaneously optimizing cathode porosity and hydrophobicity can enhance PEMFC performance.
基金the National Natural Science Foundation of China(grant nos.51971119 and 52171141)the Natural Science Foundation of Shandong Province(grant nos.ZR2020YQ32 and ZR2020QB122)+2 种基金the China Postdoctoral Science Foundation(grant no.2020M672054)the Guangdong Basic and Applied Basic Research Foundation(grant no.2021A1515111124)the Young Scholars Program of Shandong University(grant no.2019WLJH21).
文摘Developing excellent cathode catalysts with superior catalytic activities is essential for the practical application of aprotic lithium-oxygen batteries(LOBs).Herein,we successfully synthesized nitrogen-doped hollow mesoporous carbon spheres encapsulated with molybdenum disulfide(MoS_(2))nanosheets as the cathode catalyst for rechargeable LOBs,and the relationship between the battery performance and structural characteristics was intensively researched.We found that the synergistic effect of the nitrogen-doped mesoporous carbon and MoS_(2)nanosheets endows superior electrocatalytic activities to the composite catalyst.On the one hand,the nitrogen-doped mesoporous carbon could enable fast charge transfer and effectively accommodate more discharging products in the composite skeleton.On the other hand,the thin MoS_(2)nanosheets could promote mass transportation to facilitate the revisable formation and decomposition of the Li2O2 during oxygen reduction reaction and oxygen evolution reaction,and the side reactions were also prevented,apparently due to their full coverage on the composite surfaces.As a result,the catalytic cathode loaded with 2H-MoS_(2)-modified nitrogen-doped hollow mesoporous carbon spheres exhibited excellent electrochemical performance in terms of large discharge-/charge-specific capacities with low overpotentials and extended cycling life,and they hold great promise for acting as the cathode catalyst for high-performance LOBs.
基金the National Key R&D Program of China(Grant No.2021YFB4001303)the National Natural Science Foundation of China(Grant No.21975157)。
文摘High cost has undoubtedly become the biggest obstacle to the commercialization of proton exchange membrane fuel cells(PEMFCs),in which Pt-based catalysts employed in the cathodic catalyst layer(CCL)account for the major portion of the cost.Although nonprecious metal catalysts(NPMCs)show appreciable activity and stability in the oxygen reduction reaction(ORR),the performance of fuel cells based on NPMCs remains unsatisfactory compared to those using Pt-based CCL.Therefore,most studies on NPMC-based fuel cells focus on developing highly active catalysts rather than facilitating oxygen transport.In this work,the oxygen transport behavior in CCLs based on highly active Fe-N-C catalysts is comprehensively explored through the elaborate design of two types of membrane electrode structures,one containing low-Pt-based CCL and NPMCbased dummy catalyst layer(DCL)and the other containing only the NPMC-based CCL.Using Zn-N-C based DCLs of different thickness,the bulk oxygen transport resistance at the unit thickness in NPMC-based CCL was quantified via the limiting current method combined with linear fitting analysis.Then,the local and bulk resistances in NPMC-based CCLs were quantified via the limiting current method and scanning electron microscopy,respectively.Results show that the ratios of local and bulk oxygen transport resistances in NPMCbased CCL are 80%and 20%,respectively,and that an enhancement of local oxygen transport is critical to greatly improve the performance of NPMC-based PEMFCs.Furthermore,the activity of active sites per unit in NPMCbased CCLs was determined to be lower than that in the Pt-based CCL,thus explaining worse cell performance of NPMC-based membrane electrode assemblys(MEAs).It is believed that the development of NPMC-based PEMFCs should proceed not only through the design of catalysts with higher activity but also through the improvement of oxygen transport in the CCL.
基金supported by the National Science Foundations of China(Nos.21871028,22271018)。
文摘In order to advance the commercialization of rechargeable Li-air batteries,it is of importance to explore cathode catalyst with efficient catalytic activity.Transition metal oxides have poor electrical conductivity,while cobalt phosphide has excellent electrical conductivity and large specific surface area.Nevertheless,its application in organic Li-air batteries has been much less studied,and the electrocatalytic activity desires to be further elevated.Here,CoP/Co_(2)P heterojunction composite with higher polarity was fabricated.The discharge product of high-polarity CoP/Co_(2)P had a new porous box-like morphology,which was easy to be decomposed and exposed more active sites.The highly polar CoP/Co_(2)P heterostructure composite had homogeneous pores,the synergistic effect existed between CoP and Co_(2)P,and the discharge product was porous box mixed with Li_(2)O_(2)and LiOH,which made CoP/Co_(2)P achieve high specific capacity of14632 m Ah/g and cycle stably 161 times when used as air electrode cathode catalyst.This work furnished a thought for the construction of cathode catalysts with efficient catalytic activity for Li-air batteries.
基金supported by the National Natural Science Foundation of China (21375016,20475022 and 21505019)~~
文摘Noble metals, such as platinum, ruthenium and iridium‐group metals, are often used as oxygen reduction or evolution reaction （ORR/OER） electrocatalysts. To reduce the cost and provide an application of bifunctional catalysis, in this work, cobalt oxide supported on nitrogen and phospho‐rus co‐doped carbon （Co3O4/NPC） was fabricated and examined as a bifunctional electrocatalyst for OER and ORR. To prepare Co3O4/NPC, NPC was pyrolyzed from melamine and phytic acid support‐ed on carbon, followed by the solvothermal synthesis of Co3O4 on NPC. Linear sweep voltammetry was used to evaluate the activity for OER and ORR. For OER, Co3O4/NPC showed an onset potential of 0.54 V （versus the saturated calomel electrode） and a current density of 21.95 mA/cm2 at 0.80 V, which was better than both Co3O4/C and NPC. The high activity of Co3O4/NPC was attributed to a synergistic effect of the N, P co‐dopants and Co3O4. For ORR, Co3O4/NPC exhibited an activity close to commercial Pt/C in terms of the diffusion limited current density （–4.49 vs–4.76 mA/cm2 at–0.80 V）, and Co3O4 played the key role for the catalysis. Chronoamperometry （current versus time） was used to evaluate the stability, which showed that Co3O4/NPC maintained 46%current after the chronoamperometry test for OER and 95% current for ORR. Overall, Co3O4/NPC exhibited high activity and improved stability for both OER and ORR.
基金supported by the National Natural Science Foundations of China (Grants:21871028,21771024)。
文摘Combining nanomaterials with complementary properties in a well-designed structure is an effective tactic to exploit multifunctional, high-performance materials for the energy conversion and storage. Nonprecious metal catalysts, such as cobalt oxide, with superior activity and excellent stability to other catalysts are widely desired. Nevertheless, the performance of CoO nanoparticles as an electrode material were significantly limit for its inferior conductivity, dissolution, and high cohesion. Herein, we grow ultrafine cobalt monoxide to decorate the interlayer and surface of the Ti3C2 Txnanosheets via a hydrothermal method companied by calcination. The layered MXenes act as the underlying conductive substrate,which not only increase the electron transfer rate at the interface but also greatly improve the electrochemical properties of the nanosized Co O particles by restricting the aggregation of CoO. The resulting CoO/Ti3C2 Txnanomaterial is applied as oxygen electrode for lithium-oxygen battery and achieves more than 160 cycles and first cycle capacity of 16,220 mAh g-1 at 100 mA g-1. This work paves a promising avenue for constructing a bi-functional catalyst by coupling the active component of a transition metal oxide(TMO) with the MXene materials in lithium-oxygen battery.
基金financially supported by National Key R&D Program of China (No.2017YFE0195200)the Natural Science Fund of China (Nos.51871134,51672159)the Science Fund of Shandong Province (No.ZR2019MEM007)。
文摘Li-O_(2) batteries(LOBs) have been perceived as the most potential clean energy system for fast-growing electric vehicles by reason of their environmentally friendlier,high energy density and high reversibility.However,there are still some issues limiting the practical application of LOBs,such as the large gap between the actual capacity level and the theoretical capacity,low rate performance as well as short cycle life.Herein,hollow CeO_(2)/Co_(3)O_(4) polyhedrons have been synthesized by MOF template with a simple method.And it is was further served as a cathode catalyst in Li-O_(2) batteries.By means of the synergistic effect of two different transition metal oxides,nano-sized hollow porous CeO_(2)/Co_(3)O_(4) cathode obtained better capacity and cycle performance.As a result,excellent cyclability of exceeding 140 and 90 cycles are achieved at a fixed capacity of 600 and 1000 mAh/g,respectively.The successful application of this catalyst in LOBs offers a novel route in the aspect of the synthesis of other hollow porous composite oxides as catalysts for cathodes in LOBs systems by the MOF template method.
基金supported by the National Natural Science Foundation of China(Nos.52001170,21835004)the National Key R&D Program of China(Nos.2017YFA0206700,2021YFB2500300)the Natural Science Foundation of Tianjin(No.20JCQNJC02060)。
文摘Na-CO_(2) batteries have attracted extensive attention due to their high theoretical energy density(1125 Wh/kg),efficient utilization of CO_(2),and abundant sodium resources.However,they are trapped by the sluggish decomposition kinetic of discharge products (mainly Na_(2)CO_(3)) on cathode side during the charging process.Here we prepared a series of nano-composites composed of RuO_(2) nanoparticles in situ loaded on activated multi-walled carbon nanotubes (RuO_(2)@a-MWCNTs) through hydrolyzing reaction followed by calcination method and used them as cathode catalysts to accelerate the decomposition of Na_(2)CO_(3).Among all catalysts,the RuO_(2)@a-MWCNTs with appropriate ratio of RuO_(2)(49.7 wt%) demonstrated best stability and rate performance in Na-CO_(2) batteries,benefiting from both high specific surface area (160.3 m^(2)/g) and highly dispersed RuO_(2) with ultrafine nanostructures (~2 nm).At a limited capacity of 500 mAh/g,Na-CO_(2) batteries could afford the operation of over 120 cycles at 100 mA/g,and even at the current density to 500 mA/g,the charge voltage was still lower than 4.0 V after 40 cycles.Further theoretical calculations proved that RuO_(2) was the catalytically active center and contributed to the decomposition of Na_(2)CO_(3) by weakening the C=O bond.The synergetic functions of high specific surface(CNTs) and high catalytic activity (RuO_(2)) will inspire more progress on metal-CO_(2) batteries.
文摘Proton exchange membrane fuel cells(PEMFCs) are regarded as a promising sustainable energy conversion technology due to their environmental friendliness and high efficiency [1,2]. However, the sluggish kinetics of four-electron oxygen reduction reaction(ORR) result in the cathode catalysts requiring more than five times the amount of precious metal Pt compared to the anode, which limits the widespread application of PEMFCs.
基金supported by the Collaborative Innovation Center of Suzhou Nano Science and Technology,the National Natural Science Foundation of China(51725204,51572179,21471106,21771132,and 21501126)the Natural Science Foundation of Jiangsu Province(BK20161216)the 111 project and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘To tackle the issues of high cost,low durability and poor resistance to chemical poisoning of Pt-based materials as cathode catalysts for an oxygen reduction reaction(ORR),an effective method is to design and synthesize heteroatom doped carbon materials,regarded as promising electrocatalysts to replace Ptbased counterparts,due to their low cost,high stability and anti-poisoning ability.The potential of N,B co-doping has been proved by theoretical calculations,and there are still great challenges in the synthesis of such materials.Here,we employ a facile approach to obtain a N,B co-doped carbon material.The resulting material pyrolysed at 1000°C(NBC-1000)shows excellent ORR activity,exceeding that of the same type of catalysts reported so far.Not only is the NBC-1000 electrocatalyst comparable to the commercial Pt/C in terms of the onset potential,half-wave potential,diffusion limiting current density and electron transfer number,but also it has better durability and methanol tolerance than Pt/C.
基金supported by the National Natural Science Foundation of China(No.11872171 and 51802077)the Fundamental Research Funds for the Central Universities(No.B210202093).
文摘2D MXene nanosheets are regarded as promising cathode catalysts towards the hydrogen evolution reaction (HER), while their overall electrocatalytic ability still needs to be optimized before the practical application. In this contribution, we put forward a controllable assembly approach for constructing a heterostructured nanoarchitecture made from ultrafine MoS_(2) quantum dot-decorated Ti_(3)C_(2)T_(x) MXene nanosheets (MQDs/Ti_(3)C_(2)T_(x)). Benefiting from the remarkable structural features of the ultrathin catalyst layers, homogeneous MoS_(2) distribution, optimized electronic structure, and good electron conductivity, the resulting MQD/Ti_(3)C_(2)T_(x) catalyst exhibits superior HER properties with a low onset potential of 66 mV, a small Tafel slope of 74 mV dec^(-1), and a long lifespan, in contrast to the insufficient HER ability for bare MoS_(2) quantum dots and Ti_(3)C_(2)T_(x) itself. DFT calculations further disclose the optimized band structure of the MQDs/Ti_(3)C_(2)T_(x) model with numerous diverse active sites, which play fundamental roles in boosting the HER kinetics.
基金supported by the NSFC(21231005 and 21322101)the 111 Project(B12015).
文摘Rational design and synthesis of cathode catalysts are crucial for enhancing the performance of rechargeable Li-O_(2) batteries.Here,we report a controlled synthesis of the nanocomposite,Co_(3)O_(4) nanohorns coated with MnO_(2) nanosheets on a Ni foam(Co_(3)O_(4)@MnO_(2)/Ni).It integrates the catalytic activities of oxygen reduction and oxygen evolution reactions and functions as a carbon-and binder-free cathode catalyst for rechargeable Li-O_(2) batteries.This nanocomposite catalyst presents a small discharge/charge voltage gap of 0.76 V(a low polarization)and a long cycle life of 170 cycles at 300 mA g^(-1),coupled with an ionic liquid-based electrolyte,0.5 M lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide(EMITFSI),which are much better than those based on the individual Co_(3)O_(4) and MnO_(2) cathodes.The enhanced electrochemical performance is ascribed to the integrated bifunctional catalytic activities and the porous micro/nanostructure of the Co_(3)O_(4)@MnO_(2)/Ni nanocomposite,as well as the ionic liquid-based electrolyte,indicating its promising application in rechargeable Li-O_(2) batteries.
基金supported by the National Natural Science Foundation of China(Nos.52164028,22305054,52274297,22462006,22402043,52461041)the Hainan Provincial Natural Science Foundation of China(Nos.225YXQN586,224MS008)+3 种基金the Innovational Fund for Scientific and Technological Personnel of Hainan Province(No.KJRC2023C10)the Start-Up Research Foundation of Hainan University(Nos.KYQD(ZR)-21170,23169)the Collaborative Innovation Center of Marine Science and Technology,Hainan University(Nos.XTCX2022HYC01,XTCX2022HYC05)Innovative Research Project of Hainan Province(No.Qhyb2024-67)。
文摘The stability of cathode catalyst layers(CCLs)in proton exchange membrane fuel cells(PEMFCs)is critically undermined by Pt dissolution and the loss of effective gas-water management associated with carbon support corrosion.In this work,we develop a porous TiN nanotube-supported Pt(i.e.,Pt/TiN NTs)CCL that integrates robust Pt-Ti interfacial bonding with a highly accessible nanotube network to address these persistent challenges.The formation of abundant Pt-Ti bonds at the interface markedly strengthens Pt anchoring,resulting in a 2.3-fold reduction in Pt dissolution and minimal particle coarsening after accelerated durability testing compared to nanoflows-based controls dominated by Pt-N-Ti interactions.The membrane electrode assembly fabricated with this CCL achieves a peak power density of 0.81 W/cm^(2) and demonstrates exceptional durability,retaining 77%of its initial mass activity and 87.3%of its power density following aggressive square-wave potential cycling,meeting the 2025 U.S.Department of Energy benchmarks.Computational fluid dynamics simulation further reveal that the unique porous architecture facilitates efficient oxygen transport and rapid water removal,sustaining high catalytic utilization under operational conditions.This strategy establishes TiN NTs scaffolds as a generalizable solution for the next generation of carbon-free,high-stability catalyst layers,offering practical guidance for durable and efficient fuel cell design.
