查看更多>>摘要：The slow water dissociation is the rate-determining step that slows down the reaction rate in alkaline hydrogen evolution reaction(HER).Optimizing the surface electronic structure of the catalyst to lower the energy barrier of water dissociation and regulating the binding strength of adsorption intermediates are crucial strategy for boosting the catalytic performance of HER.In this study,RuO2/BaRuO3(RBRO)heterostructures with abundant oxygen vacancies and lattice distortion were in-situ constructed under a low temperature via the thermal decomposition of gel-precursor.The RBRO heterostructures obtained at 550 ℃ exhibited the highest HER activity in 1 M KOH,showing an ultra-low overpotential of 16 mV at 10 mA cm-2 and a Tafel slope of 33.37 mV dec-1.Additionally,the material demonstrated remarkable durability,with only 25 mV of degradation in overpotential after 200 h of stability testing at 10 mA cm-2.Density functional theory calculations revealed that the redistribution of charges at the heterojunction interface can optimize the binding energies of H*and OH*and effectively lower the energy barrier of water dissociation.This research offers novel perspectives on surpassing the water dis-sociation threshold of alkaline HER catalysts by means of a systematic design of heterogeneous interfaces.
查看更多>>摘要：The practical application of lithium-sulfur(Li-S)batteries,as promising next-generation batteries,is hin-dered by their shuttle effect and the slow redox kinetics.Herein,a tungsten and molybdenum nitride heterostructure functionalized with hollow metal-organic framework-derived carbon(W2N/Mo2N)was proposed as the sulfur host.The hollow spherical structure provides storage space for sulfur,enhances electrical conductivity,and inhibits volume expansion.The metal atoms in the nitrides bonded with lithium polysulfides(LiPSs)through Lewis covalent bonds,enhancing the high catalytic activity of the nitrides and effectively reducing the energy barrier of LiPSs redox conversion.Moreover,the high intrin-sic conductivity of nitrides and the ability of the heterostructure interface to accelerate electron/ion transport improved the Li+transmission.By leveraging the combined properties of strong adsorption and high catalytic activity,the sulfur host effectively inhibited the shuttle effect and accelerated the redox kinetics of LiPSs.High-efficiency Li+transmission,strong adsorption,and the efficient catalytic con-version activities of LiPSs in the heterostructure were experimentally and theoretically verified.The results indicate that the W2N/Mo2N cathode provides stable,and long-term cycling(over 2000 cycles)at 3 C with a low attenuation rate of 0.0196％per cycle.The design strategy of a twinborn nitride heterostructure thus provides a functionalized solution for advanced Li-S batteries.
查看更多>>摘要：The global energy-related CO2 emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO2 emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO2(CO2RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mecha-nisms for CO2RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low sta-bility.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO2 reduction.
查看更多>>摘要：Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane(P-VO/C)as a robust free-standing electrode.Comprehensive investigations including the finite element simulation,in-situ X-ray diffraction,and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered ZnxV2O5·nH2O,as well as superior storage kinetics with ultrahigh pseudocapacitive contribution.As demonstrated,such electrode can remain a specific capacity of 285 mA h g-1 after 100 cycles at 1 A g-1,144.4 mA h g-1 after 1500 cycles at 30 A g-1,and even 97 mA h g-1 after 3000 cycles at 60 A g-1,respectively.Unexpectedly,an impressive power density of 78.9 kW kg-1 at the super-high current density of 100 A g-1 also can be achieved.Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit,so as to promote the development of high-power energy storage devices including but not limited to AZIBs.
查看更多>>摘要：With its generality and practicality,the combination of partial charging curves and machine learning(ML)for battery capacity estimation has attracted widespread attention.However,a clear classification,fair comparison,and performance rationalization of these methods are lacking,due to the scattered exist-ing studies.To address these issues,we develop 20 capacity estimation methods from three perspectives:charging sequence construction,input forms,and ML models.22,582 charging curves are generated from 44 cells with different battery chemistry and operating conditions to validate the performance.Through comprehensive and unbiased comparison,the long short-term memory(LSTM)based neural network exhibits the best accuracy and robustness.Across all 6503 tested samples,the mean absolute percentage error(MAPE)for capacity estimation using LSTM is 0.61％,with a maximum error of only 3.94％.Even with the addition of 3 mV voltage noise or the extension of sampling intervals to 60 s,the average MAPE remains below 2％.Furthermore,the charging sequences are provided with physical explanations related to battery degradation to enhance confidence in their application.Recommendations for using other competitive methods are also presented.This work provides valuable insights and guidance for estimat-ing battery capacity based on partial charging curves.
查看更多>>摘要：The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion batteries.Nevertheless,the broad application prospect is obstructed by the sluggish Na+kinetics and the phase transitions upon cycling.Herein,we establish the thermodynamically stable phase diagram of various Mn-based oxide composites precisely controlled by sodium content tailoring strategy coupling with co-doping and solid-state reaction.The chemical environment of the P2/P'3 and P2/P3 biphasic composites indicate that the charge compensation mech-anism stems from the cooperative contribution of anions and cations.Benefiting from the no phase tran-sition to scavenge the structure strain,P2/P'3 electrode can deliver long cycling stability(capacity retention of 73.8％after 1000 cycles at 10 C)and outstanding rate properties(the discharge capacity of 84.08 mA h g-1 at 20 C)than P2/P3 electrode.Furthermore,the DFT calculation demonstrates that the introducing novel P'3 phase can significantly regulate the Na+reaction dynamics and modify the local electron configuration of Mn.The effective phase engineering can provide a reference for designing other high-performance electrode materials for Na-ion batteries.
查看更多>>摘要：Nickel(Ni)-rich cathode materials have become promising candidates for the next-generation electrical vehicles due to their high specific capacity.However,the poor thermodynamic stability(including cyclic performance and safety performance or thermal stability)will restrain their wide commercial applica-tion.Herein,a single-crystal Ni-rich LiNi0.83Co0.12Mn0.05O2 cathode material is synthesized and modified by a dual-substitution strategy in which the high-valence doping element improves the structural stabil-ity by forming strong metal-oxygen binding forces,while the low-valence doping element eliminates high Li+/Ni2+mixing.As a result,this synergistic dual substitution can effectively suppress H2-H3 phase transition and generation of microcracks,thereby ultimately improving the thermodynamic stability of Ni-rich cathode material.Notably,the dual-doped Ni-rich cathode delivers an extremely high capacity retention of 81％after 250 cycles(vs.Li/Li+)in coin-type half cells and 87％after 1000 cycles(vs.gra-phite/Li+)in pouch-type full cells at a high temperature of 55 ℃.More impressively,the dual-doped sam-ple exhibits excellent thermal stability,which demonstrates a higher thermal runaway temperature and a lower calorific value.The synergetic effects of this dual-substitution strategy pave a new pathway for addressing the critical challenges of Ni-rich cathode at high temperatures,which will significantly advance the high-energy-density and high-safety cathodes to the subsequent commercialization.
查看更多>>摘要：Transition metal carbides and nitrides(MXenes)nanosheets are attractive two-dimensional(2D)mate-rials,but they suffer from oxidation/degradation issues during storage and/or applications due to their sensitivity to water and oxygen.Despite the great research progress,the exact oxidation kinetics of Ti3C2Tx(MXene)and their final products after oxidation are not fully understood.Herein,we systemat-ically tracked the oxidation process of few-layer Ti3C2Tx nanosheets in an aqueous solution at room tem-perature over several weeks.We also studied the oxidation effects on the electrocatalytic properties of Ti3C2Tx for hydrogen evolution reaction and found that the overpotential to achieve a current density of 10 mA cm-2 increases from 0.435 to 0.877 V after three weeks of degradation,followed by improve-ment to stabilized values of around 0.40 V after eight weeks.These results suggest that severely oxidized MXene could be a promising candidate for designing efficient catalysts.According to our detailed exper-imental characterization and theoretical calculations,unlike previous studies,black titanium oxide is formed as the final product in addition to white Ti(Ⅳ)oxide and disordered carbons after the complete oxidation of Ti3C2Tx.This work presents significant advancements in better understanding of 2D Ti3C2Tx(MXene)oxidation and enhances the prospects of this material for various applications.
查看更多>>摘要：Due to its low cost and natural abundance of sodium,Na-ion batteries(NIBs)are promising candidates for large-scale energy storage systems.The development of ultralow voltage anode materials is of great sig-nificance in improving the energy density of NIBs.Low-voltage anode materials,however,are severely lacking in NIBs.Of all the reported insertion oxides anodes,the Na2Ti3O7 has the lowest operating voltage(an average potential of 0.3 V vs.Na+/Na)and is less likely to deposit sodium,which has excellent poten-tial for achieving NIBs with high energy densities and high safety.Although significant progress has been made,achieving Na2Ti3O7 electrodes with excellent performance remains a severe challenge.This paper systematically summarizes and discusses the physicochemical properties and synthesis methods of Na2Ti3O7.Then,the sodium storage mechanisms,key issues and challenges,and the optimization strate-gies for the electrochemical performance of Na2Ti3O7 are classified and further elaborated.Finally,remaining challenges and future research directions on the Na2Ti3O7 anode are highlighted.This review offers insights into the design of high-energy and high-safety NIBs.
查看更多>>摘要：Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increasing optical absorption,refining energy levels,and improving molecular packing in organic semiconductors.Herein,a series of NFAs(PzIC-4H,PzIC-4F,PzIC-4Cl,PzIC-2Br)with phenazine as the central core and with/without halogen-substituted(dicyanomethylidene)-indan-1-one(IC)as the electron-accepting end group were synthesized,and the effect of end group matched phenazine cen-tral unit on the photovoltaic performance was systematically studied.Synergetic photophysical and mor-phological analyses revealed that the PM6∶PzIC-4F blend involves efficient exciton dissociation,higher charge collection and transfer rates,better crystallinity,and optimal phase separation.Therefore,OSCs based on PM6∶PzIC-4F as the active layer exhibited a PCE of 16.48％with an open circuit voltage(Voc)and energy loss of 0.880 V and 0.53 eV,respectively.Accordingly,this work demonstrated a promising approach by designing phenazine-based NFAs for achieving high-performance OSCs.
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