The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the ...The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.展开更多
Li-rich Mn-based oxides(LRMO)are of great significance in achieving high energy density all-solid-state lithium batteries(ASSLBs),owing to their high theoretical capacity and high operation voltage.Unfortunately,their...Li-rich Mn-based oxides(LRMO)are of great significance in achieving high energy density all-solid-state lithium batteries(ASSLBs),owing to their high theoretical capacity and high operation voltage.Unfortunately,their practical application is hindered by severe interface degradation due to the chemical oxidation and electrochemical decomposition of solid electrolytes(SEs),driven by high-active oxygen and electron sources from LRMO.Herein,an interfacial modification strategy is proposed to stabilize the surface lattice oxygen of LRMO and reduce electronic conduction between LRMO and SEs,synergistically.Accordingly,the byproducts from chemical oxidation(InO^(-))and electrochemical decomposition(LiCl^(-))are largely suppressed,leading to superior interfacial transport with the lowest resistance.Consequently,the ASSLB achieves a high reversible capacity of 227.9 mA h g^(-1)at 0.1 C,a cycling stability of 90.1%capacity retention after 200 cycles at 0.1 C,and a superior rate capability with a capacity of81.7 m A h g^(-1)at 3.0 C.This study enriches the fundamental understanding of LRMO/SEs interfacial evolution during the electrochemical cycling and the proposed interfacial modification strategy benefits the future design of Li-rich compounds for ASSLBs.展开更多
A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese(Mn^(2+))and ammonium(NH_(4)^(+)-N).Three different combinations of oxidants(KMnO_(4)and K_(2)FeO_(4))and ...A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese(Mn^(2+))and ammonium(NH_(4)^(+)-N).Three different combinations of oxidants(KMnO_(4)and K_(2)FeO_(4))and reductants(MnSO_(4)and FeCl_(2))were used during the start-up period.Filter R3 started up by KMnO_(4)and FeCl_(2)(Mn^(7+)→MnO_(x))exhibited excellent catalytic property,and the NH_(4)^(+)-N and Mn^(2+)removal efficiency reached over 80%on the 10th and 35th days,respectively.Filter R1 started up by K_(2)FeO_(4)and MnSO_(4)(MnO_(x)←Mn^(2+))exhibited the worst catalytic property.Filter R2 started up by KMnO_(4)and MnSO_(4)(Mn^(7+)→MnO_(x)←Mn^(2+))were in between.According to Zeta potential results,the Mn-based oxides(MnO_(x))formed by Mn^(7+)→MnO_(x)performed the highest pHIEP and pHPZC.The higher the pHIEP and pHPZC,the more unfavorable the cation adsorption.However,it was inconsistent with its excellent Mn^(2+)and NH_(4)^(+)-N removal abilities,implying that catalytic oxidation played a key role.Combined with XRD and XPS analysis,the results showed that the MnO_(x)produced by the reduction of KMnO_(4)showed early formation of buserite crystals,high degree of amorphous,high content of Mn3+and lattice oxygen with the higher activity to form defects.The above results showed that MnO_(x)produced by the reduction of KMnO_(4)was more conducive to the formation of active species for catalytic oxidation of NH_(4)^(+)-N and Mn^(2+)removal.This study provides new insights on the formation mechanisms of the active MnO_(x)that could catalytic oxidation of NH_(4)^(+)-N and Mn^(2+).展开更多
The as-spun Ti_(1−x)La_(x)Fe_(0.8)Mn_(0.2)(x=0,0.01,0.03,0.06,0.09,molar fraction)alloys were prepared by melt spinning.The effects of La substitution for Ti on the microstructure,hydrogen storage kinetics and thermod...The as-spun Ti_(1−x)La_(x)Fe_(0.8)Mn_(0.2)(x=0,0.01,0.03,0.06,0.09,molar fraction)alloys were prepared by melt spinning.The effects of La substitution for Ti on the microstructure,hydrogen storage kinetics and thermodynamics of TiFe-type Ti−Fe−Mn-based alloy were investigated.The as-spun alloys hold the TiFe single phase,which transforms to TiFeH_(0.06),TiFeH,and TiFeH_(2) hydrides after hydrogenation.La substitution promotes the formation of micro-defects(such as dislocations and grain boundaries)in the alloys,thus facilitating hydrogen diffusion.In addition,the hydrogen storage kinetics properties are improved after introducing La element.With the rise of La content,the hydrogen storage capacity decreases firstly and then increases,but the absolute value of hydriding enthalpy change(|ΔH|)increases firstly and then reduces.When x=0.01,the maximum value of|ΔH|is obtained to be(25.23±0.50)kJ/mol for hydriding,and the alloy has the maximum hydrogen absorption capacity of(1.80±0.04)wt.%under the conditions of 323 K and 3 MPa.展开更多
Mn-based oxides have been regarded as a promising family of cathode materials for high-performance lithium-ion batteries,but the practical applications have been limited because of severe capacity deterioration(such a...Mn-based oxides have been regarded as a promising family of cathode materials for high-performance lithium-ion batteries,but the practical applications have been limited because of severe capacity deterioration(such as Li Mn O_(2)and Li Mn_(2)O_(4))as well as further complications from successive structure changes during cycling,low initial coulombic efficiency(such as Li-rich cathode)and oxidization of organic carbonate solvents at high charge potential(such as Li Ni0.5 Mn1.5 O4).Large amounts of efforts have been concentrated on resolving these issues towards practical applications,and many vital progresses have been carried out.Hence,the primary target of this review is focused on different proposed strategies and breakthroughs to enhance the rate performance and cycling stability of nanostructured Mn-based oxide cathode materials for Li-ion batteries,including morphology control,ion doping,surface coatings,composite construction.The combination of delicate architectures with conductive species represents the perspective ways to enhance the conductivity of the cathode materials and further buffer the structure transformation and strain during cycling.At last,based on the elaborated progress,several perspectives of Mn-based oxide cathodes are summarized,and some possible attractive strategies and future development directions of Mn-based oxide cathodes with enhanced electrochemical properties are proposed.The review will offer a detailed introduction of various strategies enhancing electrochemical performance and give a novel viewpoint to shed light on the future innovation in Mn-based oxide cathode materials,which benefits the design and construction of high-performance Mn-based oxide cathode materials in the future.展开更多
Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage.However,their commercial applications are hindered by irreversible capacity lo...Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage.However,their commercial applications are hindered by irreversible capacity loss in the first charge-discharge process,voltage decay during cycling,inefficient cyclability and rate capability.Many attempts have been performed to solve such issues,including the mechanism study and strategies to improve the electrochemical performance.This article provides a brief review and future perspective on the main challenges of the high-capacity Li-rich Mn-based cathodes for Li-ion batteries.展开更多
The high-rate cyclability of Li-rich Mn-based oxide(LMO)is highly limited by the electrochemical polarization resulting from the slow kinetic of the Li2MnO3 phase.Herein,the Prussian blue(PB)coating layer with specifi...The high-rate cyclability of Li-rich Mn-based oxide(LMO)is highly limited by the electrochemical polarization resulting from the slow kinetic of the Li2MnO3 phase.Herein,the Prussian blue(PB)coating layer with specific redox potential is introduced as a functionalized interface to overcome the side effect and the escaping of O on the surface of LMO,especially its poor rate capability.In detail,the PB layer can restrict the large polarization of LMO by sharing overloaded current at a high rate due to the synchronous redox of PB and LMO.Consequently,an enhanced high rate performance with capacity retention of 87.8%over 300 cycles is obtained,which is superior to 50.5%of the pristine electrode.Such strategies on the high-rate cyclability of Li-rich Mn-based oxide compatible with good low-rate performances may attract great attention for pursuing durable performances.展开更多
The rapid expansion of renewable energies asks for great progress of energy-storage technologies for sustainable energy supplies,which raises the compelling demand of high-performance rechargeable batteries.To satisfy...The rapid expansion of renewable energies asks for great progress of energy-storage technologies for sustainable energy supplies,which raises the compelling demand of high-performance rechargeable batteries.To satisfy the huge demand from the coming energy-storage market,the resource and cost-effectiveness of rechargeable batteries become more and more important.Manganese(Mn)as a key transition element with advantages including high abundance,low cost,and low toxicity derives various kinds(spinels,layered oxides,polyanions,Prussian blue analogs,etc.)of high-performance Mn-based electrode materials,especially cathodes,for rechargeable batteries ranging from Li-ion batteries,Na-ion batteries,aqueous batteries,to multivalent metal-ion batteries.It is anticipated that Mn-based materials with Mn as the major transition-metal element will constitute a flourishing family of Mn-based rechargeable batteries(Mn RBs)for large-scale and differentiated energy-storage applications.On the other hand,several critical issues including Jahn-Teller effect,Mn dissolution,and O release greatly hinder the pace of Mn RBs,which require extensive material optimizations and battery/system improvements.This review aims to provide an investigation about Mn-based materials and batteries for the coming energy-storage demands,with compelling issues and challenges that must be overcome.展开更多
Catalytic ozonation is a potential technology to eliminate refractory organic contaminants with the low concentration in secondary effluent from industrial park wastewater treatment plants(IPWWTPs).In this study,the c...Catalytic ozonation is a potential technology to eliminate refractory organic contaminants with the low concentration in secondary effluent from industrial park wastewater treatment plants(IPWWTPs).In this study,the catalytic ozonation over the Mn-based catalyst significantly improved the chemical oxygen demand(COD),total organic carbon(TOC),and UV254 removals of secondary effluent from IPWWTPs.The Mn-based catalyst/Og system achieved 84.8%,69.8%,and 86.4% removals of COD,TOC,and UY254,which were 3.3,5.7,and 1.1 times that in ozonation alone,respectively.Moreover,the Mn-based catalytic ozonation process exhibited excellent pH tolerance ranging from pH 4.0 to 9.0.Additionally,the depth analysis based on fluorescence excitation-emission matrix(EEM)confirmed that the catalytic ozonation process preferred to degrade toxic aromatic hydrocarbons.The existence of the Mn-based catalyst/O_(3) system enhanced 21.4%-38.3% more fluorescent organic matters removal,compared to that in ozonation alone.Mechanistic studies proved that the abundant Lewis acid sites(Mn/Mn(n+1)+and adsorbed oxygen)on the surface of the Mn-based catalyst effectively promoted O_(3) decomposition into reactive oxygen species(ROS),and-O_(2)-/HO_(2):and ^(1)O_(2) were the main ROS for degrading refractory organic contaminants.The contributions of ROS oxidation(91.2%)was much higher than that of direct O_(3) oxidation(8.8%).Thus,this work provides an effective advanced treatment process for purifying secondary effluent from IPWWTPs.展开更多
Searching for a renewable energy system is always the goal to fulfill sustainable development for the future.Water oxidation is considered as a crucial reaction to attain sustainable energy systems.Inspired by the bio...Searching for a renewable energy system is always the goal to fulfill sustainable development for the future.Water oxidation is considered as a crucial reaction to attain sustainable energy systems.Inspired by the biological Mn_(4)CaO_(5)cluster,considerable effort has been devoted to developing highly efficient Mn-based heterogeneous catalysts and exploring intrinsic mechanism for water oxidation.This review begins with describing the structural characteristics of the Mn_(4)Ca O_(5)cluster and the proposed catalytic cycle.Then,the structural characteristics of synthetic Mn-based heterogeneous catalyst are summarized,with emphasis on the understanding of reaction mechanisms and the rate-determining steps.Finally,the strategy of understanding the catalytic mechanism of Mn-based water oxidation is prospected.展开更多
Mn-based oxides are promising cathode materials for potassium-ion batteries due to their high theoretical ca-pacity and abundant raw materials.However,the anisotropic properties of their conventional polycrystalline s...Mn-based oxides are promising cathode materials for potassium-ion batteries due to their high theoretical ca-pacity and abundant raw materials.However,the anisotropic properties of their conventional polycrystalline structures lead to insufficient rate capability and cycle life.Here,a single-crystal Mn-based layered oxide,P3′-type K_(0.35)Mn_(0.8)Fe_(0.1)Cu_(0.1)O_(2)(KMFCO),is designed and synthesized through a bimetallic co-induction effect and used as a cathode for potassium-ion battery.Benefiting from a unique single-crystal structure that is devoid of grain boundaries,it achieves a higher Kþtransport rate and a reduced volume change during the Kþintercalation/deintercalation process.Accordingly,the single-crystal P3′-type KMFCO delivers superior rate capability(52.9 mAh g^(-1) at 1000 mA g^(-1))and excellent cycling stability(91.1%capacity retention after 500 cycles at 500 mA g^(-1)).A full cell assembled with the P3′-type KMFCO cathode and a graphite anode also exhibits a high reversible capacity(81.2 mAh g^(-1) at 100 mA g^(-1))and excellent cycling performance(97%capacity retention after 300 cycles).The strategy of developing single-crystal materials may offer a new pathway for maintaining structural stability and improving the rate capability of layered manganese oxide cathodes and beyond.展开更多
Sodium-ion batteries (SIBs) have great potential in large-scale energy storage applications due to the low cost and abundance of sodium resources (1,2)However, some critical issues, such as low energy density and infe...Sodium-ion batteries (SIBs) have great potential in large-scale energy storage applications due to the low cost and abundance of sodium resources (1,2)However, some critical issues, such as low energy density and inferior cycling performance, definitely hinder the practical application of SIBs, in part because of the bigger and heavier Na ion in contrast with the Li ion as an energy carrier (3)Recently, a surge of attention has been paid to the Mnbased materials due to the earth abundant and environmentally friendly manganese element [4,5].展开更多
Construction of iridium(Ir)based active sites on certain acid stable supports now is a general strategy for the development of low-Ir OER catalysts.Atomically doped Ir in the lattice of acid stableγ-MnO_(2) has been ...Construction of iridium(Ir)based active sites on certain acid stable supports now is a general strategy for the development of low-Ir OER catalysts.Atomically doped Ir in the lattice of acid stableγ-MnO_(2) has been recently achieved,which shows high activity and stability though Ir usage was reduced more than 95%than that in current commercial proton exchange membrane water electrolyzer(PEMWE).However,the activity and stability enhancement by Ir doping inγ-MnO_(2) still remains elusive.Herein,high dispersion of iridium(up to 1.37 atom%)doping in the lattice ofγ-MnO_(2) has been achieved by optimizing the thermal decomposition of the iridium precursors.Benefiting from atomic dispersive doping of Ir,the optimized Ir-MnO_(2) catalyst shows high OER activity,as it has turnover frequency of 0.655 s^(–1) at an overpotential of 300 mV in 0.5 mol L^(-1) H_(2)SO_(4).The catalyst also shows high stability,as it can sustainably work at 100 mA cm^(-2) for 24 h.Experimental and theoretical studies reveal that Ir is preferentially doped intoβphase rather than R phase,and the Ir site is the active site for OER.The OER active site is postulated to be Ir^(5+)-O(H)-Mn^(3+)unit structure on the surface.Furthermore,Ir doping changes the potential determining step from the formation of O*to the formation of*OOH,emphasizing the promoting effect toward OER derived from Ir sites.This work not only demonstrates the possibility of achieving atomic-level doping of Ir on the surface of a support to dramatically reduce Ir usage,but also,more importantly,reveals the mechanism behind accounting for the stability and activity enhancement by Ir doping.These important findings may serve as valuable guidance for further development of more efficient,stable and cost-effective low Ir-based OER catalysts for PEMWE.展开更多
Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we d...Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we demonstrate the improved low-temperature activity and N_(2)selectivity by regulating the redox and acidic properties of MnCe oxides supported on etched ZSM-5 supports.The etched ZSM-5 enables the highly dispersed state of MnCeOx species and strong interaction between Mn and Ce species,which promotes the reduction of CeO2,facilitates electron transfer from Mn to Ce,and generates more Mn^(4+)and Ce^(3+)species.The strong redox capacity contributes to forming the reactive nitrate species and-NH_(2)species from oxidative dehydrogenation of NH_(3).Moreover,the adsorbed NH_(3)and-NH_(2)species are the reactive intermediates that promote the formation of N_(2).This work demonstrates an effective strategy to enhance the low-temperature activity and N_(2)selectivity of SCR catalysts,contributing to the NO_(x)control for the low-temperature exhaust gas during the cold-start of diesel vehicles.展开更多
The application of Li-rich Mn-based cathodes, the most promising candidates for high-energy-density Liion batteries, in all-solid-state batteries can further enhance the safety and stability of battery systems.However...The application of Li-rich Mn-based cathodes, the most promising candidates for high-energy-density Liion batteries, in all-solid-state batteries can further enhance the safety and stability of battery systems.However, the utilization of high-capacity Li-rich cathodes has been limited by sluggish kinetics and severe interfacial issues in all-solid-state batteries. Here, a multi-functional interface modification strategy involving dispersed submicron single-crystal structure and multi-functional surface modification layer obtained through in-situ interfacial chemical reactions was designed to improve the electrochemical performance of Li-rich Mn-based cathodes in all-solid-state batteries. The design of submicron single-crystal structure promotes the interface contact between the cathode particles and the solid-state electrolyte,and thus constructs a more complete ion and electron conductive network in the composite cathode.Furthermore, the Li-gradient layer and the lithium molybdate coating layer constructed on the surface of single-crystal Li-rich particles accelerate the transport of Li ions at the interface, suppress the side reactions between cathodes and electrolyte, and inhibit the oxygen release on the cathode surface. The optimized Li-rich cathode materials exhibit excellent electrochemical performance in halide all-solid-state batteries. This study emphasizes the vital importance of reaction kinetics and interfacial stability of Lirich cathodes in all-solid-state batteries and provides a facile modification strategy to enhance the electrochemical performance of all-solid-state batteries based on Li-rich cathodes.展开更多
Aqueous potassium-ion batteries(APIBs),recognized as safe and reliable new energy devices,are considered as one of the alternatives to traditional batteries.Layered MnO_(2),serving as the main cathode,exhibits a lower...Aqueous potassium-ion batteries(APIBs),recognized as safe and reliable new energy devices,are considered as one of the alternatives to traditional batteries.Layered MnO_(2),serving as the main cathode,exhibits a lower specific capacity in aqueous electrolytes compared to organic systems and operates through a different reaction mechanism.The application of highly conductive graphene may effectively enhance the capacity of APIBs but could complicate the potassium storage environment.In this study,a MnO_(2) cathode pre-intercalated with K~+ions and grown on graphene(KMO@rGO) was developed using the microwave hydrothermal method for APIBs.KMO@rGO achieved a specific capacity of 90 mA h g^(-1) at a current density of 0.1 A g^(-1),maintaining a capacity retention rate of>90% after 5000 cycles at 5 A g^(-1).In-situ and exsitu characterization techniques revealed the energy-storage mechanism of KMO@rGO:layered MnO_(2)traps a large amount of "dead" water molecules during K~+ions removal.However,the introduction of graphene enables these water molecules to escape during K~+ ions insertion at the cathode.The galvanostatic intermittent titration technique and density functional theory confirmed that KMO@rGO has a higher K~+ions migration rate than MnO_(2).Therefore,the capacity of this cathode depends on the interaction between dead water and K~+ions during the energy-storage reaction.The optimal structural alignment between layered MnO_(2) and graphene allows electrons to easily flow into the external circuit.Rapid charge compensation forces numerous low-solvent K~+ions to displace interlayer dead water,enhancing the capacity.This unique reaction mechanism is unprecedented in other aqueous battery studies.展开更多
Ca-type todorokite catalysts were designed and prepared by a simple redox method and applied to the selective reduction of NO_(x) by NH_(3)(NH_(3)-SCR)for the first time.Compared with the Na-type manjiroite prepared b...Ca-type todorokite catalysts were designed and prepared by a simple redox method and applied to the selective reduction of NO_(x) by NH_(3)(NH_(3)-SCR)for the first time.Compared with the Na-type manjiroite prepared by the same method,the todorokite catalysts with different Mn/Ca ratios showed greatly improved catalytic activity for NO_(x) reduction.Among them,Mn8Ca4 catalyst exhibited the best NH_(3)-SCR performance,achieving 90%NO_(x) conversion within temperature range of 70-275℃ and having a high sulphur resistance.Compared to the Na-type manjiroite sample,Ca-type todorokite catalysts possessed an increased size of tunnel,resulting in a larger specific surface area.As increased the amounts of Ca doping,the Na content in Ca-type todorokite catalysts significantly decreased,providing larger amounts of Bronsted acid sites for NH_(3) adsorption to produce NH_(4)^(+).The NH_(4)^(+)species were highly active for reaction with NO+O_(2),playing a determining role in NH_(3)-SCR process at low temperatures.Meanwhile,larger amounts of surface adsorbed oxygen contained over the Ca-doping samples than that over Na-type manjiroite,promoting the oxidation of NO and fast SCR processes.Over the Ca-type todorokite catalysts,furthermore,nitrates produced during the flow of NO+O_(2),were more active for reaction with NH_(3) than that over Na-type manjiroite,benefiting the occurrence of NH_(3)-SCR process.This study provides novel insights into the design of NH_(3)-SCR catalysts with high performance.展开更多
Development of hydrothermally stable,low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge.We have prepared a metal oxide-zeolite composite catalyst by dep...Development of hydrothermally stable,low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge.We have prepared a metal oxide-zeolite composite catalyst by depositing Mn active species on a mixture support of CeO_(2)/Al_(2)O_(3) and ZSM-5.This composite catalyst is hydrothermally stable and shows improved low-temperature SCR activity and significantly reduced N_(2)O formation than the corresponding metal oxide catalyst.Comparing with a Cu-CHA catalyst,the composite catalyst has a faster response to NH_(3) injection and less NH_(3) slip.Our characterization results reveal that such an oxide-zeolite composite catalyst contains more acidic sites and Mn^(3+)species as a result of oxide-zeolite interaction,and this interaction leads to the generation of more NH_(4)^(+)species bound to the Br?nsted acid sites and more reactive NOxspecies absorbed on the Mn sites.Herein,we report our mechanistic understanding of the oxide-zeolite composite catalyst and its molecular pathway for improving the low-temperature activity and N_(2) selectivity for NH_(3)-SCR reaction.Practically,this work may provide an alternative methodology for low-temperature NO_(x) control from diesel vehicles.展开更多
Mn-based layered oxides are among the most promising cathode materials for sodium-ion batteries owing to the advantages of abundance,environmenta friendliness,low cost and high specific capacity.P2 and O'3 are two...Mn-based layered oxides are among the most promising cathode materials for sodium-ion batteries owing to the advantages of abundance,environmenta friendliness,low cost and high specific capacity.P2 and O'3 are two representative structures of Mn-based layered oxides.However,the P2 structure containing insufficien Na generally exhibits low initial charge capacity,while O'3structure with sufficient Na delivers high initial charge capacity but poor cycle stability.This study prepared a multitude of Na_(x)MnO_(2)(x=0.7,0.8,0.9)cathode materials with varying P2/O'3 ratios and further investigated their electrochemical performances.The optimized Na_(0.8)MnO_(2) comprising 69.9 wt%O'3 and 30.1 wt%P2 phase,exhibited relatively balanced specific capacity,Coulombic efficiency and cycle stability.Specifically,it achieved a high specific capacity of 128.9 mAh·g^(-1) with an initia Coulombic efficiency of 98.2%in half-cell configuration The Na_(0.8)MnO_(2)//hard carbon full cell also achieved a high specific capacity of 126.7 mAh·g^(-1) with an initia Coulombic efficiency of 98.9%.Moreover,the capacity fading mechanism was revealed by combining in-situ and ex-situ X-ray diffraction.The findings of this study provide theoretical guidance for further modification design of Mnbased layered cathodes.展开更多
Commercial lithium-ion batteries (LIBs) have been widely used in various energy storage systems. However, many unfavorable factors of LIBs have prompted researchers to turn their attention to the development of emergi...Commercial lithium-ion batteries (LIBs) have been widely used in various energy storage systems. However, many unfavorable factors of LIBs have prompted researchers to turn their attention to the development of emerging secondary batteries. Aqueous zinc ion batteries (AZIBs) present some prominent advantages with environmental friendliness, low cost and convenient operation feature. MnO_(2) electrode is the first to be discovered as promising cathode material. So far, manganese-based oxides have made significant progresses in improving the inherent capacity and energy density. Herein, we summarize comprehensively recent advances of Mn-based compounds as electrode materials for ZIBs. Especially, this review focuses on the design strategies of electrode structures, optimization of the electrochemical performance and the clarification of energy storage mechanisms. Finally, their future research directions and perspective are also proposed.展开更多
基金supported by the National Key R&D Program of China(No.2022YFB2404400)the National Natural Science Foundation of China(Nos.U23A20577,52372168,92263206 and 21975006)+1 种基金the“The Youth Beijing Scholars program”(No.PXM2021_014204_000023)the Beijing Natural Science Foundation(Nos.2222001 and KM202110005009).
文摘The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.
基金supported by the National Natural Science Foundation of China with Grant No.12274176 and No.12474210supported by the relevant national program+1 种基金support from Department of Science and Technology of Jilin Province with Grant No.20210301021GXthe Fundamental Research Funds for the Center Universities with Grant No.2023-JCXK-03。
文摘Li-rich Mn-based oxides(LRMO)are of great significance in achieving high energy density all-solid-state lithium batteries(ASSLBs),owing to their high theoretical capacity and high operation voltage.Unfortunately,their practical application is hindered by severe interface degradation due to the chemical oxidation and electrochemical decomposition of solid electrolytes(SEs),driven by high-active oxygen and electron sources from LRMO.Herein,an interfacial modification strategy is proposed to stabilize the surface lattice oxygen of LRMO and reduce electronic conduction between LRMO and SEs,synergistically.Accordingly,the byproducts from chemical oxidation(InO^(-))and electrochemical decomposition(LiCl^(-))are largely suppressed,leading to superior interfacial transport with the lowest resistance.Consequently,the ASSLB achieves a high reversible capacity of 227.9 mA h g^(-1)at 0.1 C,a cycling stability of 90.1%capacity retention after 200 cycles at 0.1 C,and a superior rate capability with a capacity of81.7 m A h g^(-1)at 3.0 C.This study enriches the fundamental understanding of LRMO/SEs interfacial evolution during the electrochemical cycling and the proposed interfacial modification strategy benefits the future design of Li-rich compounds for ASSLBs.
基金supported by the National Natural Science Foundation of China(No.52000145)the Youth Innovation Team of Shaanxi Universities,China(No.2019No.19)+1 种基金the Key Scientific Research Projects of Education Department of Shaanxi Province,China(No.22JY035)the Project of Youth Talent Lift Program of Shaanxi Association for Science and Technology,China(No.20230447).
文摘A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese(Mn^(2+))and ammonium(NH_(4)^(+)-N).Three different combinations of oxidants(KMnO_(4)and K_(2)FeO_(4))and reductants(MnSO_(4)and FeCl_(2))were used during the start-up period.Filter R3 started up by KMnO_(4)and FeCl_(2)(Mn^(7+)→MnO_(x))exhibited excellent catalytic property,and the NH_(4)^(+)-N and Mn^(2+)removal efficiency reached over 80%on the 10th and 35th days,respectively.Filter R1 started up by K_(2)FeO_(4)and MnSO_(4)(MnO_(x)←Mn^(2+))exhibited the worst catalytic property.Filter R2 started up by KMnO_(4)and MnSO_(4)(Mn^(7+)→MnO_(x)←Mn^(2+))were in between.According to Zeta potential results,the Mn-based oxides(MnO_(x))formed by Mn^(7+)→MnO_(x)performed the highest pHIEP and pHPZC.The higher the pHIEP and pHPZC,the more unfavorable the cation adsorption.However,it was inconsistent with its excellent Mn^(2+)and NH_(4)^(+)-N removal abilities,implying that catalytic oxidation played a key role.Combined with XRD and XPS analysis,the results showed that the MnO_(x)produced by the reduction of KMnO_(4)showed early formation of buserite crystals,high degree of amorphous,high content of Mn3+and lattice oxygen with the higher activity to form defects.The above results showed that MnO_(x)produced by the reduction of KMnO_(4)was more conducive to the formation of active species for catalytic oxidation of NH_(4)^(+)-N and Mn^(2+)removal.This study provides new insights on the formation mechanisms of the active MnO_(x)that could catalytic oxidation of NH_(4)^(+)-N and Mn^(2+).
基金financial supports from the Inner Mongolia Natural Science Foundation,China (No.2019BS05005)the Inner Mongolia University of Science and Technology Innovation Fund,China (No.2019QDL-B11)the National Natural Science Foundation of China (Nos.51901105, 51871125, 51761032).
文摘The as-spun Ti_(1−x)La_(x)Fe_(0.8)Mn_(0.2)(x=0,0.01,0.03,0.06,0.09,molar fraction)alloys were prepared by melt spinning.The effects of La substitution for Ti on the microstructure,hydrogen storage kinetics and thermodynamics of TiFe-type Ti−Fe−Mn-based alloy were investigated.The as-spun alloys hold the TiFe single phase,which transforms to TiFeH_(0.06),TiFeH,and TiFeH_(2) hydrides after hydrogenation.La substitution promotes the formation of micro-defects(such as dislocations and grain boundaries)in the alloys,thus facilitating hydrogen diffusion.In addition,the hydrogen storage kinetics properties are improved after introducing La element.With the rise of La content,the hydrogen storage capacity decreases firstly and then increases,but the absolute value of hydriding enthalpy change(|ΔH|)increases firstly and then reduces.When x=0.01,the maximum value of|ΔH|is obtained to be(25.23±0.50)kJ/mol for hydriding,and the alloy has the maximum hydrogen absorption capacity of(1.80±0.04)wt.%under the conditions of 323 K and 3 MPa.
基金financially supported by the National Natural Science Foundation of China(no.51672120)the Scientific Research Project of Mudanjiang Normal University(no.1355JG014)+1 种基金the Natural Science Foundation of Hebei Province of China(no.B2020501003)the Fundamental Research Funds for the Central Universities(no.N2023030)。
文摘Mn-based oxides have been regarded as a promising family of cathode materials for high-performance lithium-ion batteries,but the practical applications have been limited because of severe capacity deterioration(such as Li Mn O_(2)and Li Mn_(2)O_(4))as well as further complications from successive structure changes during cycling,low initial coulombic efficiency(such as Li-rich cathode)and oxidization of organic carbonate solvents at high charge potential(such as Li Ni0.5 Mn1.5 O4).Large amounts of efforts have been concentrated on resolving these issues towards practical applications,and many vital progresses have been carried out.Hence,the primary target of this review is focused on different proposed strategies and breakthroughs to enhance the rate performance and cycling stability of nanostructured Mn-based oxide cathode materials for Li-ion batteries,including morphology control,ion doping,surface coatings,composite construction.The combination of delicate architectures with conductive species represents the perspective ways to enhance the conductivity of the cathode materials and further buffer the structure transformation and strain during cycling.At last,based on the elaborated progress,several perspectives of Mn-based oxide cathodes are summarized,and some possible attractive strategies and future development directions of Mn-based oxide cathodes with enhanced electrochemical properties are proposed.The review will offer a detailed introduction of various strategies enhancing electrochemical performance and give a novel viewpoint to shed light on the future innovation in Mn-based oxide cathode materials,which benefits the design and construction of high-performance Mn-based oxide cathode materials in the future.
基金This work was supported by NSFC(21621091)National Key Research and Development of China(2016YFB0100202)+4 种基金Natural Science Foundation of Fujian Province(2015J01063)the support of National Materials Genome Project(2016YFB0700600)National Key R&D Program of China(2016YFB0700600)the Guangdong Innovation Team Project(No.2013N080)Shenzhen Science and Technology Research(Nos.JCYJ20151015162256516,JCYJ20150729111733470 and JCYJ20160226105838578)。
文摘Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage.However,their commercial applications are hindered by irreversible capacity loss in the first charge-discharge process,voltage decay during cycling,inefficient cyclability and rate capability.Many attempts have been performed to solve such issues,including the mechanism study and strategies to improve the electrochemical performance.This article provides a brief review and future perspective on the main challenges of the high-capacity Li-rich Mn-based cathodes for Li-ion batteries.
基金supported by the National Natural Science Foundation of China (51802261,52072298,and 52172228)the Natural Science Foundation of Shaanxi (2019GHJD-13 and 2020JC-41)+2 种基金the Natural Science Basic Research Plan in Shaanxi province of China (2019JLP-04)Xi'an Science and Technology Project of China (2019219714SYS012CG034)the foundation of National Key Laboratory (6142808200202),PR China.
文摘The high-rate cyclability of Li-rich Mn-based oxide(LMO)is highly limited by the electrochemical polarization resulting from the slow kinetic of the Li2MnO3 phase.Herein,the Prussian blue(PB)coating layer with specific redox potential is introduced as a functionalized interface to overcome the side effect and the escaping of O on the surface of LMO,especially its poor rate capability.In detail,the PB layer can restrict the large polarization of LMO by sharing overloaded current at a high rate due to the synchronous redox of PB and LMO.Consequently,an enhanced high rate performance with capacity retention of 87.8%over 300 cycles is obtained,which is superior to 50.5%of the pristine electrode.Such strategies on the high-rate cyclability of Li-rich Mn-based oxide compatible with good low-rate performances may attract great attention for pursuing durable performances.
基金financially supported by the National Key R&D Program of China(2022YFB2404400)the National Natural Science Foundation of China(92263206,21875007,21975006,21974007,and U19A2018)+1 种基金the Youth Beijing Scholars program(PXM2021_014204_000023)the Beijing Natural Science Foundation(2222001 and KZ202010005007)。
文摘The rapid expansion of renewable energies asks for great progress of energy-storage technologies for sustainable energy supplies,which raises the compelling demand of high-performance rechargeable batteries.To satisfy the huge demand from the coming energy-storage market,the resource and cost-effectiveness of rechargeable batteries become more and more important.Manganese(Mn)as a key transition element with advantages including high abundance,low cost,and low toxicity derives various kinds(spinels,layered oxides,polyanions,Prussian blue analogs,etc.)of high-performance Mn-based electrode materials,especially cathodes,for rechargeable batteries ranging from Li-ion batteries,Na-ion batteries,aqueous batteries,to multivalent metal-ion batteries.It is anticipated that Mn-based materials with Mn as the major transition-metal element will constitute a flourishing family of Mn-based rechargeable batteries(Mn RBs)for large-scale and differentiated energy-storage applications.On the other hand,several critical issues including Jahn-Teller effect,Mn dissolution,and O release greatly hinder the pace of Mn RBs,which require extensive material optimizations and battery/system improvements.This review aims to provide an investigation about Mn-based materials and batteries for the coming energy-storage demands,with compelling issues and challenges that must be overcome.
基金supported by the National Natural Science Foundation of China(No.U22A20241).
文摘Catalytic ozonation is a potential technology to eliminate refractory organic contaminants with the low concentration in secondary effluent from industrial park wastewater treatment plants(IPWWTPs).In this study,the catalytic ozonation over the Mn-based catalyst significantly improved the chemical oxygen demand(COD),total organic carbon(TOC),and UV254 removals of secondary effluent from IPWWTPs.The Mn-based catalyst/Og system achieved 84.8%,69.8%,and 86.4% removals of COD,TOC,and UY254,which were 3.3,5.7,and 1.1 times that in ozonation alone,respectively.Moreover,the Mn-based catalytic ozonation process exhibited excellent pH tolerance ranging from pH 4.0 to 9.0.Additionally,the depth analysis based on fluorescence excitation-emission matrix(EEM)confirmed that the catalytic ozonation process preferred to degrade toxic aromatic hydrocarbons.The existence of the Mn-based catalyst/O_(3) system enhanced 21.4%-38.3% more fluorescent organic matters removal,compared to that in ozonation alone.Mechanistic studies proved that the abundant Lewis acid sites(Mn/Mn(n+1)+and adsorbed oxygen)on the surface of the Mn-based catalyst effectively promoted O_(3) decomposition into reactive oxygen species(ROS),and-O_(2)-/HO_(2):and ^(1)O_(2) were the main ROS for degrading refractory organic contaminants.The contributions of ROS oxidation(91.2%)was much higher than that of direct O_(3) oxidation(8.8%).Thus,this work provides an effective advanced treatment process for purifying secondary effluent from IPWWTPs.
基金supported by the Starting Research Funds of Shaanxi Normal University and the National Natural Science Foundation of China(21872092)。
文摘Searching for a renewable energy system is always the goal to fulfill sustainable development for the future.Water oxidation is considered as a crucial reaction to attain sustainable energy systems.Inspired by the biological Mn_(4)CaO_(5)cluster,considerable effort has been devoted to developing highly efficient Mn-based heterogeneous catalysts and exploring intrinsic mechanism for water oxidation.This review begins with describing the structural characteristics of the Mn_(4)Ca O_(5)cluster and the proposed catalytic cycle.Then,the structural characteristics of synthetic Mn-based heterogeneous catalyst are summarized,with emphasis on the understanding of reaction mechanisms and the rate-determining steps.Finally,the strategy of understanding the catalytic mechanism of Mn-based water oxidation is prospected.
基金B.Wang acknowledges the National Natural Science Foundation of China,China(No.U1904198)B.Lu acknowledges the National Natural Science Foundation of China,China(No.U20A20247 and 51922038).
文摘Mn-based oxides are promising cathode materials for potassium-ion batteries due to their high theoretical ca-pacity and abundant raw materials.However,the anisotropic properties of their conventional polycrystalline structures lead to insufficient rate capability and cycle life.Here,a single-crystal Mn-based layered oxide,P3′-type K_(0.35)Mn_(0.8)Fe_(0.1)Cu_(0.1)O_(2)(KMFCO),is designed and synthesized through a bimetallic co-induction effect and used as a cathode for potassium-ion battery.Benefiting from a unique single-crystal structure that is devoid of grain boundaries,it achieves a higher Kþtransport rate and a reduced volume change during the Kþintercalation/deintercalation process.Accordingly,the single-crystal P3′-type KMFCO delivers superior rate capability(52.9 mAh g^(-1) at 1000 mA g^(-1))and excellent cycling stability(91.1%capacity retention after 500 cycles at 500 mA g^(-1)).A full cell assembled with the P3′-type KMFCO cathode and a graphite anode also exhibits a high reversible capacity(81.2 mAh g^(-1) at 100 mA g^(-1))and excellent cycling performance(97%capacity retention after 300 cycles).The strategy of developing single-crystal materials may offer a new pathway for maintaining structural stability and improving the rate capability of layered manganese oxide cathodes and beyond.
文摘Sodium-ion batteries (SIBs) have great potential in large-scale energy storage applications due to the low cost and abundance of sodium resources (1,2)However, some critical issues, such as low energy density and inferior cycling performance, definitely hinder the practical application of SIBs, in part because of the bigger and heavier Na ion in contrast with the Li ion as an energy carrier (3)Recently, a surge of attention has been paid to the Mnbased materials due to the earth abundant and environmentally friendly manganese element [4,5].
文摘Construction of iridium(Ir)based active sites on certain acid stable supports now is a general strategy for the development of low-Ir OER catalysts.Atomically doped Ir in the lattice of acid stableγ-MnO_(2) has been recently achieved,which shows high activity and stability though Ir usage was reduced more than 95%than that in current commercial proton exchange membrane water electrolyzer(PEMWE).However,the activity and stability enhancement by Ir doping inγ-MnO_(2) still remains elusive.Herein,high dispersion of iridium(up to 1.37 atom%)doping in the lattice ofγ-MnO_(2) has been achieved by optimizing the thermal decomposition of the iridium precursors.Benefiting from atomic dispersive doping of Ir,the optimized Ir-MnO_(2) catalyst shows high OER activity,as it has turnover frequency of 0.655 s^(–1) at an overpotential of 300 mV in 0.5 mol L^(-1) H_(2)SO_(4).The catalyst also shows high stability,as it can sustainably work at 100 mA cm^(-2) for 24 h.Experimental and theoretical studies reveal that Ir is preferentially doped intoβphase rather than R phase,and the Ir site is the active site for OER.The OER active site is postulated to be Ir^(5+)-O(H)-Mn^(3+)unit structure on the surface.Furthermore,Ir doping changes the potential determining step from the formation of O*to the formation of*OOH,emphasizing the promoting effect toward OER derived from Ir sites.This work not only demonstrates the possibility of achieving atomic-level doping of Ir on the surface of a support to dramatically reduce Ir usage,but also,more importantly,reveals the mechanism behind accounting for the stability and activity enhancement by Ir doping.These important findings may serve as valuable guidance for further development of more efficient,stable and cost-effective low Ir-based OER catalysts for PEMWE.
基金the National Natural Science Foundation of China(Nos.22125604,22106100,21976117,22276119)Shanghai Rising-Star Program(No.22QA1403700).
文摘Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we demonstrate the improved low-temperature activity and N_(2)selectivity by regulating the redox and acidic properties of MnCe oxides supported on etched ZSM-5 supports.The etched ZSM-5 enables the highly dispersed state of MnCeOx species and strong interaction between Mn and Ce species,which promotes the reduction of CeO2,facilitates electron transfer from Mn to Ce,and generates more Mn^(4+)and Ce^(3+)species.The strong redox capacity contributes to forming the reactive nitrate species and-NH_(2)species from oxidative dehydrogenation of NH_(3).Moreover,the adsorbed NH_(3)and-NH_(2)species are the reactive intermediates that promote the formation of N_(2).This work demonstrates an effective strategy to enhance the low-temperature activity and N_(2)selectivity of SCR catalysts,contributing to the NO_(x)control for the low-temperature exhaust gas during the cold-start of diesel vehicles.
基金National Key R&D Program of China (2023YFB2503900)National Natural Science Foundation of China (22222904, 22179133 and 12374176)CAS Project for Young Scientists in Basic Research (YSBR-058)。
文摘The application of Li-rich Mn-based cathodes, the most promising candidates for high-energy-density Liion batteries, in all-solid-state batteries can further enhance the safety and stability of battery systems.However, the utilization of high-capacity Li-rich cathodes has been limited by sluggish kinetics and severe interfacial issues in all-solid-state batteries. Here, a multi-functional interface modification strategy involving dispersed submicron single-crystal structure and multi-functional surface modification layer obtained through in-situ interfacial chemical reactions was designed to improve the electrochemical performance of Li-rich Mn-based cathodes in all-solid-state batteries. The design of submicron single-crystal structure promotes the interface contact between the cathode particles and the solid-state electrolyte,and thus constructs a more complete ion and electron conductive network in the composite cathode.Furthermore, the Li-gradient layer and the lithium molybdate coating layer constructed on the surface of single-crystal Li-rich particles accelerate the transport of Li ions at the interface, suppress the side reactions between cathodes and electrolyte, and inhibit the oxygen release on the cathode surface. The optimized Li-rich cathode materials exhibit excellent electrochemical performance in halide all-solid-state batteries. This study emphasizes the vital importance of reaction kinetics and interfacial stability of Lirich cathodes in all-solid-state batteries and provides a facile modification strategy to enhance the electrochemical performance of all-solid-state batteries based on Li-rich cathodes.
基金financially supported by the Scientific and Technological Plan Project of Guizhou Province (Grant No. [2021]060)the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and the Graduate Joint Training Base at Guizhou University (Grant No. 2020-520000-83-01-324061)the Guizhou Engineering Research Center for smart services (Grant No. 2203-520102-04-04-298868)。
文摘Aqueous potassium-ion batteries(APIBs),recognized as safe and reliable new energy devices,are considered as one of the alternatives to traditional batteries.Layered MnO_(2),serving as the main cathode,exhibits a lower specific capacity in aqueous electrolytes compared to organic systems and operates through a different reaction mechanism.The application of highly conductive graphene may effectively enhance the capacity of APIBs but could complicate the potassium storage environment.In this study,a MnO_(2) cathode pre-intercalated with K~+ions and grown on graphene(KMO@rGO) was developed using the microwave hydrothermal method for APIBs.KMO@rGO achieved a specific capacity of 90 mA h g^(-1) at a current density of 0.1 A g^(-1),maintaining a capacity retention rate of>90% after 5000 cycles at 5 A g^(-1).In-situ and exsitu characterization techniques revealed the energy-storage mechanism of KMO@rGO:layered MnO_(2)traps a large amount of "dead" water molecules during K~+ions removal.However,the introduction of graphene enables these water molecules to escape during K~+ ions insertion at the cathode.The galvanostatic intermittent titration technique and density functional theory confirmed that KMO@rGO has a higher K~+ions migration rate than MnO_(2).Therefore,the capacity of this cathode depends on the interaction between dead water and K~+ions during the energy-storage reaction.The optimal structural alignment between layered MnO_(2) and graphene allows electrons to easily flow into the external circuit.Rapid charge compensation forces numerous low-solvent K~+ions to displace interlayer dead water,enhancing the capacity.This unique reaction mechanism is unprecedented in other aqueous battery studies.
基金supported by Self-deployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(No.E055C003)the National Natural Science Foundation of China(Nos.U20B6004 and 22072179)
文摘Ca-type todorokite catalysts were designed and prepared by a simple redox method and applied to the selective reduction of NO_(x) by NH_(3)(NH_(3)-SCR)for the first time.Compared with the Na-type manjiroite prepared by the same method,the todorokite catalysts with different Mn/Ca ratios showed greatly improved catalytic activity for NO_(x) reduction.Among them,Mn8Ca4 catalyst exhibited the best NH_(3)-SCR performance,achieving 90%NO_(x) conversion within temperature range of 70-275℃ and having a high sulphur resistance.Compared to the Na-type manjiroite sample,Ca-type todorokite catalysts possessed an increased size of tunnel,resulting in a larger specific surface area.As increased the amounts of Ca doping,the Na content in Ca-type todorokite catalysts significantly decreased,providing larger amounts of Bronsted acid sites for NH_(3) adsorption to produce NH_(4)^(+).The NH_(4)^(+)species were highly active for reaction with NO+O_(2),playing a determining role in NH_(3)-SCR process at low temperatures.Meanwhile,larger amounts of surface adsorbed oxygen contained over the Ca-doping samples than that over Na-type manjiroite,promoting the oxidation of NO and fast SCR processes.Over the Ca-type todorokite catalysts,furthermore,nitrates produced during the flow of NO+O_(2),were more active for reaction with NH_(3) than that over Na-type manjiroite,benefiting the occurrence of NH_(3)-SCR process.This study provides novel insights into the design of NH_(3)-SCR catalysts with high performance.
基金in part supported by BASF Environmental Catalyst and Metal Solutionsthe support of the National Natural Science Foundation of China(Nos.21976117,22125604 and 22276119)the sponsor by“Chenguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.21CGA48)。
文摘Development of hydrothermally stable,low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge.We have prepared a metal oxide-zeolite composite catalyst by depositing Mn active species on a mixture support of CeO_(2)/Al_(2)O_(3) and ZSM-5.This composite catalyst is hydrothermally stable and shows improved low-temperature SCR activity and significantly reduced N_(2)O formation than the corresponding metal oxide catalyst.Comparing with a Cu-CHA catalyst,the composite catalyst has a faster response to NH_(3) injection and less NH_(3) slip.Our characterization results reveal that such an oxide-zeolite composite catalyst contains more acidic sites and Mn^(3+)species as a result of oxide-zeolite interaction,and this interaction leads to the generation of more NH_(4)^(+)species bound to the Br?nsted acid sites and more reactive NOxspecies absorbed on the Mn sites.Herein,we report our mechanistic understanding of the oxide-zeolite composite catalyst and its molecular pathway for improving the low-temperature activity and N_(2) selectivity for NH_(3)-SCR reaction.Practically,this work may provide an alternative methodology for low-temperature NO_(x) control from diesel vehicles.
基金supported by the Natural Science Research Project of Anhui Province Education Department(No.2022AH050334)the Scientific Research Foundation of Anhui University of Technology for Talent Introduction(No.DT2200001211)the New Energy Electric Vehicles High-Voltage Components Inspection and Testing Public Service Platform。
文摘Mn-based layered oxides are among the most promising cathode materials for sodium-ion batteries owing to the advantages of abundance,environmenta friendliness,low cost and high specific capacity.P2 and O'3 are two representative structures of Mn-based layered oxides.However,the P2 structure containing insufficien Na generally exhibits low initial charge capacity,while O'3structure with sufficient Na delivers high initial charge capacity but poor cycle stability.This study prepared a multitude of Na_(x)MnO_(2)(x=0.7,0.8,0.9)cathode materials with varying P2/O'3 ratios and further investigated their electrochemical performances.The optimized Na_(0.8)MnO_(2) comprising 69.9 wt%O'3 and 30.1 wt%P2 phase,exhibited relatively balanced specific capacity,Coulombic efficiency and cycle stability.Specifically,it achieved a high specific capacity of 128.9 mAh·g^(-1) with an initia Coulombic efficiency of 98.2%in half-cell configuration The Na_(0.8)MnO_(2)//hard carbon full cell also achieved a high specific capacity of 126.7 mAh·g^(-1) with an initia Coulombic efficiency of 98.9%.Moreover,the capacity fading mechanism was revealed by combining in-situ and ex-situ X-ray diffraction.The findings of this study provide theoretical guidance for further modification design of Mnbased layered cathodes.
基金supported by the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure (No. SKL201904SIC)State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology)(No. 2020-KF-12)the Opening Project of State Key Laboratory of Metastable Materials Science and Technology (No. 202007)。
文摘Commercial lithium-ion batteries (LIBs) have been widely used in various energy storage systems. However, many unfavorable factors of LIBs have prompted researchers to turn their attention to the development of emerging secondary batteries. Aqueous zinc ion batteries (AZIBs) present some prominent advantages with environmental friendliness, low cost and convenient operation feature. MnO_(2) electrode is the first to be discovered as promising cathode material. So far, manganese-based oxides have made significant progresses in improving the inherent capacity and energy density. Herein, we summarize comprehensively recent advances of Mn-based compounds as electrode materials for ZIBs. Especially, this review focuses on the design strategies of electrode structures, optimization of the electrochemical performance and the clarification of energy storage mechanisms. Finally, their future research directions and perspective are also proposed.
