查看更多>>摘要：The oxygen evolution reaction(OER)is a crucial step in metal-air batteries and water splitting technolo-gies,playing a significant role in the efficiency and achievable heights of these two technologies.However,the OER is a four-step,four-electron reaction,and its slow kinetics result in high overpotentials,posing a challenge.To address this issue,numerous strategies involving modified catalysts have been proposed and proven to be highly efficient.In these strategies,the introduction of strain has been widely reported because it is generally believed to effectively regulate the electronic structure of metal sites and alter the adsorption energy of catalyst surfaces with reaction intermediates.However,strain has many other effects that are not well known,making it an important yet unexplored area.Based on this,this review provides a detailed introduction to the various roles of strain in OER.To better explain these roles,the review also presents the definition of strain and elucidates the potential mechanisms of strain in OER based on the d-band center theory and adsorption volcano plot.Additionally,the review showcases var-ious ways of introducing strain in OER through examples reported in the latest literature,aiming to pro-vide a comprehensive perspective for the development of strain engineering.Finally,the review analyzes the appropriate proportion of strain introduction,compares compressive and tensile strain,and examines the impact of strain on stability.And the review offers prospects for future research directions in this emerging field.
查看更多>>摘要：Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of elec-trochemical CO2 reduction reactions,where understanding the structure-activity relationship is essential for catalyst design.Herein,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu nanowires.When tested in a flow cell,the Cu-Ag catalyst with Ag nanopar-ticles on the bottom achieved a faradaic efficiency of 54％for ethylene production,much higher than the catalyst with Ag nanoparticles on the top.The catalysts were further studied in the H-cell and zero-gap MEA cell.It was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic catalysts.Our work elucidates the structure-activity relationship of bimetallic catalysts for CO2 reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity.
查看更多>>摘要：Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and is regarded as a future technology for production of CO2-free pure hydrogen.Herein,a heterostructural Pt-Ir dual-layer electrode is developed and shown to achieve successful long-term oper-ation in an ammonia electrolyzer with an anion exchange membrane(AEM).This electrolyzer consisted of eight membrane electrode assemblies(MEAs)with a total geometric area of 200 cm2 on the anode side,which resulted in a hydrogen production rate of 25 L h-1.We observed the degradation in MEA perfor-mance attributed to changes in the anode catalyst layer during hydrogen production via ammonia elec-trolysis.Furthermore,we demonstrated the relationship between the ammonia oxidation reaction(AOR)and the oxygen evolution reaction(OER).
查看更多>>摘要：Compared with organic electrolytes,aqueous electrolytes exhibit significantly higher ionic conductivity and possess inherent safety features,showcasing unique advantages in supercapacitors.However,chal-lenges remain for low-salt aqueous electrolytes operating at high voltage and low temperature.Herein,we report a low-salt(0.87 m,m means mol kg-1)'salt in dimethyl sulfoxide/water'hybrid electrolyte with non-flammability via hybridizing aqueous electrolyte with an organic co-solvent of dimethyl sulfox-ide(hydrogen bond acceptor).As a result,the 0.87 m hybrid electrolyte exhibits enhanced electrochem-ical stability,a freezing temperature below-50 ℃,and an outstanding ionic conductivity of 0.52 mS cm-1 at-50 ℃.Dimethyl sulfoxide can anchor water molecules through intermolecular hydrogen bond interaction,effectively reinforcing the stability of water in the hybrid electrolyte.Furthermore,the interaction between dimethyl sulfoxide and water molecules diminishes the involvement of water in the generation of ordered ice crystals,finally facilitating the low-temperature performance of the hybrid electrolyte.When paired with the 0.87 m'salt in dimethyl sulfoxide/water'hybrid electrolyte,the symmetric supercapacitor presents a 2.0 V high operating voltage at 25 ℃,and can operate stably at-50 ℃.Importantly,the suppressed electrochemical reaction of water at-50 ℃ further leads to the symmetric supercapacitor operated at a higher voltage of 2.6 V.This modification strategy opens an effec-tive avenue to develop low-salt electrolytes for high-voltage and low-temperature aqueous supercapacitors.
查看更多>>摘要：Manufacturing process,diffusion co-efficient and areal capacity are the three main criteria for regulating thick electrodes for lithium-ion batteries(LIBs).However,simultaneously regulating these criteria for LIBs is desirable but remains a significant challenge.In this work,niobium pentoxide(Nb2O5)anode and lithium iron phosphate(LiFePO4)cathode materials were chosen as the model materials and demon-strate that these three parameters can be simultaneously modulated by incorporation of micro-carbon fibers(MCF)and carbon nanotubes(CNT)with both Nb2O5 and LFP via vacuum filtration approach.Both as-prepared MNC-20 anode and MLC-20 cathode achieves high reversible areal capacity of ≈5.4 m A h cm-2@0.1 C and outstanding Li-ion diffusion coefficients of ≈10-8 cm2 s-1 in the half-cell configura-tion.The assembled MNC-20||MLC-20 full cell LIB delivers maximum energy and power densities of 244.04 W h kg-1 and 108.86 W kg-1,respectively.The excellent electrochemical properties of the as-prepared thick electrodes can be attributed to the highly conductive,mechanical compactness and mul-tidimensional mutual effects of the MCF,CNT and active materials that facilitates rapid Li-ion diffusion kinetics.Furthermore,electrochemical impedance spectroscopy(E1S),symmetric cells analysis,and in-situ Raman techniques clearly validates the enhanced Li-ion diffusion kinetics in the present architecture.
查看更多>>摘要：Solid polymer electrolytes(SPEs)have become increasingly important in advanced lithium-ion batteries(LIBs)due to their improved safety and mechanical properties compared to organic liquid electrolytes.Cross-linked polymers have the potential to further improve the mechanical property without trading off Li-ion conductivity.In this study,focusing on a recently developed cross-linked SPE,i.e.,the one based on poly(vinylene carbonate)-poly(ethylene oxide)cross-linked network(PVCN),we used solid-state nuclear magnetic resonance(NMR)techniques to investigate the fundamental interaction between the chain segments and Li ions,as well as the lithium-ion motion.By utilizing homonuclear/heteronuclear correlation,CP(cross-polarization)kinetics,and spin-lattice relaxation experiments,etc.,we revealed the structural characteristics and their relations to lithium-ion mobilities.It is found that the network formation prevents poly(ethylene oxide)chains from crystallization,which could create sufficient space for segmental tumbling and Li-ion conduction.As such,the mechanical property is greatly improved with even higher Li-ion mobilities compared to the poly(vinylene carbonate)or poly(ethylene oxide)based SPE analogues.
查看更多>>摘要：This review addresses the growing interest for potassium-ion full-cells(KIFCs)in view of the transition from potassium-ion half-cells(KIHCs)toward commercial K-ion batteries(KIBs).It focuses on the key parameters of KIFCs such as the electrode/electrolyte interfaces challenge,major barriers,and recent advancements in KIFCs.The strategies for enhancing KIFC performance,including interfaces control,elec-trolyte optimization,electrodes capacity ratio,electrode material screening and electrode design,are dis-cussed.The review highlights the need to evaluate KIBs in full-cell configurations as half-cell results are strongly impacted by the K metal reactivity.It also emphasizes the importance of understanding solid electrolyte interphase(SEI)formation in KIFCs and explores promising nonaqueous as well as quasi-and all-solid-state electrolytes options.This review thus paves the way for practical,cost-effective,and scalable KIBs as energy storage systems by offering insights and guidance for future research.
查看更多>>摘要：The interface mechanism between catalyst and carbon substrate has been the focus of research.In this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple one-step pyrolysis strategy.The experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electron transfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon material.The FeCo/S-NC catalysts show outstanding performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).FeCo/S-NC shows a high half-wave potential(E1/2=0.8823 V)for ORR and a low overpo-tential at 10 mA cm-2(Ej-10-299 mV)for OER.In addition,compared with Pt/C+Ru02 assembled Zn-air battery(ZAB),the FeCo/S-NC assembled ZAB exhibits a larger power density(198.8 mW cm-2),a higher specific capacity(786.1 mA h gZn-1),and ultra-stable cycle performance.These results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergisti-cally enhance the electrochemical performance.
查看更多>>摘要：O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na+diffusion pathways during cycling,resulting in com-promised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O3-NaNi0.5Mn0.5O2 to effec-tively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na+diffusion pathways but also orchestrates a mild phase transition by sup-pressing the Na+/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na0.95Ca0.05Ni0.5Mn0.5O1.95F0.05(NNMO-CaF)exhibits a mild O3-O3+O'3 → P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g-1 at a current density of 120 mA g-1 with a capacity retention of 87.1％after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na+diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.
查看更多>>摘要：Although metallic rhodium(Rh)is regarded as a promising platinum-alternative anode catalyst of direct methanol fuel cell(DMFC),the conventional"particle-to-face"contact model between Rh and matrix lar-gely limits the overall electrocatalytic performance due to their insufficient cooperative effects.Herein,we report a controllable and robust heterointerface engineering strategy for the bottom-up fabrication of rhombic Rh nanosheets in situ confined on Ti3C2Tx MXene nanolamellas(Rh NS/MXene)via a conve-nient stereoassembly process.This unique design concept gives the resulting 2D/2D Rh NS/MXene heterostructure intriguing textural features,including large accessible surface areas,strong"face-to-face"interfacial interactions,homogeneous Rh nanosheet distribution,ameliorative electronic structure,and high electronic conductivity.As a consequence,the as-prepared Rh NS/MXene nanoarchitectures exhibit exceptional electrocatalytic methanol oxidation properties in terms of a large electrochemically active surface area of 126.2 m2 gRh-1,a high mass activity of 1056.9 mA mgRh-1,and a long service life,which significantly outperform those of conventional particle-shaped Rh catalysts supported by carbon black,carbon nanotubes,reduced graphene oxide,and MXene matrixes as well as the commercial Pt nanoparticle/carbon black and Pd nanoparticle/carbon black catalysts with the same noble metal loading amount.Density functional theory calculations further demonstrate that the direct electronic interaction at the well-contacted 2D/2D heterointerfaces effectively enhances the adsorption energy of Rh nanosheets and induces a left shift of the d-band center,thereby making the Rh NS/MXene configuration suffer less from CO poisoning.This work highlights the importance of rational heterointerface design in the construction of advanced noble metal/MXene electrocatalysts,which may provide new avenues for developing the next-generation DMFC devices.
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