查看更多>>摘要：Aqueous zinc-ion batteries are regarded as the promising candidates for large-scale energy storage systems owing to low cost and high safety;however,their applications are restricted by their poor low-temperature performance.Herein,a low-temperature electrolyte for low-temperature aqueous zinc-ion batteries is designed by introducing low-polarity diglyme into an aqueous solution of Zn(ClO4)2.The diglyme disrupts the hydrogen-bonding network of water and lowers the freezing point of the electrolyte to-105 ℃.The designed electrolyte achieves ionic conductivity up to 16.18 mS cm 1 at-45 ℃.The diglyme and ClO4 reconfigure the solvated structure of Zn2+,which is more favorable for the desolvation of Zn2+at low temperatures.In addition,the diglyme effectively suppresses the dendrites,hydrogen evolution reaction,and by-products of the zinc anode,improving the cycle stability of the battery.At-20 ℃,a Zn‖Zn symmetrical cell is cycled for 5200 h at 1 mA cm-2 and 1 mA h cm-2,and a Zn‖polyaniline battery achieves an ultra-long cycle life of 10 000 times.This study sheds light on the future design of electrolytes with high ionic conductivity and easy desolvation at low temperatures for rechargeable batteries.
查看更多>>摘要：The separator is an essential component of sodium-ion batteries(SIBs)to determine their electrochemical performances.However,the separator with high mechanical strength,good electrolyte wettability and excellent electrochemical performance remains an open challenge.Herein,a new separator consisting of amphoteric nanofibers with abundant functional groups was fabricated through supramolecular assembly of natural polymers for SIB.The uniform nanoporous structure,remarkable mechanical properties and abundant functional groups(e.g.-COOH,-NH2 and-OH)endow the separator with lower dissolution activation energy and higher ion migration numbers.These metrics enable the separator to lower the barrier for desolvation of Na+,accelerate the migration of Na+,and generate more stable solid electrolyte interphase(SEI)and cathode electrolyte interphase(CEI).The battery assembled with the amphoteric nanofiber separator shows higher specific capacity and better stability than that assembled with glass fiber(GF)separator.
查看更多>>摘要：Since 2019,research into MXene derivatives has seen a dramatic rise;further progress requires a rational design for specific functionality.Herein,through a molecular design by selecting suitable functional groups in the MXene coating,we have implemented the dual N doping of the derivatives,nitrogen-doped TiO2@nitrogen-doped carbon nanosheets(N-TiO2@NC),to strike a balance between the active anatase TiO2 at low temperatures,and carbon activation at high temperatures.The NH3 reduction environment generated at 400 ℃ as evidenced by the in situ pyrolysis SVUV-PIMS process is crucial for concurrent phase engineering.With both electrical conductivity and surface Na+availability,the N-TiO2@NC achieves higher interface capacitive-like sodium storage with long-term stability.More than 100 mAh g-1 is achieved at 2 A g1 after 5000 cycles.The proposed design may be extended to other MXenes and solidify the growing family of MXene derivatives for energy storage.
查看更多>>摘要：Calcium-ion batteries have been considered attractive candidates for large-scale energy storage applications due to their natural abundance and low redox potential of Ca2+/Ca.However,current calcium ion technology is still hampered by the lack of high-capacity and long-life electrode materials to accommodate the large Ca2+(1.00 Å).Herein,an amorphous vanadium structure induced by Mo doping and in-situ electrochemical activation is reported as a high-rate anode material for calcium ion batteries.The doping of Mo could destroy the lattice stability of VS4 material,enhancing the flexibility of the structure.The following electrochemical activation further converted the material into sulfide and oxides co-dominated composite(defined as MoVSO),which serves as an active material for the storage of Ca2+during cycling.Consequently,this amorphous vanadium structure exhibits excellent rate capability,achieving discharge capacities of 306.7 and 149.2 mAh g-1 at 5 and 50 A g-1 and an ultra-long cycle life of 2000 cycles with 91.2％capacity retention.These values represent the highest level to date reported for calcium ion batteries.The mechanism studies show that the material undergoes a partial phase transition process to derive MoVSO.This work unveiled the calcium storage mechanism of vanadium sulfide in aqueous electrolytes and accelerated the development of high-performance aqueous calcium ion batteries.
查看更多>>摘要：KVPO4F with excellent structural stability and high operating voltage has been identified as a promising cathode for potassium-ion batteries(PIBs),but limits in sluggish ion transport and severe volume change cause insufficient potassium storage capability.Here,a high-energy and low-strain KVPO4F composite cathode assisted by multifunctional K2C4O4 electrode stabilizer is exquisitely designed.Systematical electrochemical investigations demonstrate that this composite cathode can deliver a remarkable energy density up to 530 Wh kg-1 with 142.7 mAh g-1 of reversible capacity at 25 mA g-1,outstanding rate capability of 70.6 mAh g-1 at 1000 mA g-1,and decent cycling stability.Furthermore,slight volume change(～5％)and increased interfacial stability with thin and even cathode-electrolyte interphase can be observed through in situ and ex situ characterizations,which are attributed to the synergistic effect from in situ potassium compensation and carbon deposition through self-sacrificing K2C4O4 additive.Moreover,potassium-ion full cells manifest significant improvement in energy density and cycling stability.This work demonstrates a positive impact of K2C4O4 additive on the comprehensive electrochemical enhancement,especially the activation of high-voltage plateau capacity and provides an efficient strategy to enlighten the design of other high-voltage cathodes for advanced high-energy batteries.
查看更多>>摘要：Aluminum(Al)-ion batteries have emerged as a potential alternative to conventional ion batteries that rely on less abundant and costly materials like lithium.Nonetheless,given the nascent stage of advancement in Al-ion batteries(AIBs),attaining electrode materials that can leverage both intercalation capacity and structural stability remains challenging.Herein,we demonstrate a C3N4-derived layered N,S heteroatom-doped carbon,obtained at different pyrolysis temperatures,as a cathode material for AIBs,encompassing the diffusion-controlled intercalation and surface-induced capacity with ultrahigh reversibility.The developed layered N,S-doped corbon(N,S-C)cathode,synthesized at 900 ℃,delivers a specific capacity of 330 mAhg-1 with a relatively high coulombic efficiency of～85％after 500 cycles under a current density of 0.5 A g-1.Owing to its reinforced adsorption capability and enlarged interlayer spacing by doping N and S heteroatoms,the N,S-C900 cathode demonstrates outstanding energy storage capacity with excellent rate performance(61 mAhg-1 at 20 A g-1)and ultrahigh reversibility(90 mAhg-1 at 5Ag-1 after 10000cycles).
查看更多>>摘要：Electrocatalytic reduction of CO2 into high energy-density fuels and value-added chemicals under mild conditions can promote the sustainable cycle of carbon and decrease current energy and environmental problems.Constructing electrocatalyst with high activity,selectivity,stability,and low cost is really matter to realize industrial application of electrocatalytic CO2 reduction(ECR).Metal-nitrogen-carbon(M-N-C),especially Ni-N-C,display excellent performance,such as nearly 100％CO selectivity,high current density,outstanding tolerance,etc.,which is considered to possess broad application prospects.Based on the current research status,starting from the mechanism of ECR and the existence form of Ni active species,the latest research progress of Ni-N-C electrocatalysts in CO2 electroreduction is systematically summarized.An overview is emphatically interpreted on the regulatory strategies for activity optimization over Ni-N-C,including N coordination modulation,vacancy defects construction,morphology design,surface modification,heteroatom activation,and bimetallic cooperation.Finally,some urgent problems and future prospects on designing Ni-N-C catalysts for ECR are discussed.This review aims to provide the guidance for the design and development of Ni-N-C catalysts with practical application.
查看更多>>摘要：Hydrogen spillover effect has recently garnered a lot of attention in the field of electrocatalytic hydrogen evolution reactions.A new avenue for understanding the dynamic behavior of atomic migration in which hydrogen atoms moving on a catalyst surface was opened up by the setup of the word"hydrogen spillover."However,there is currently a dearth of thorough knowledge regarding the hydrogen spillover effect.Currently,the advancement of sophisticated characterization procedures offers progressively useful information to enhance our grasp of the hydrogen spillover effect.The understanding of material fabrication for hydrogen spillover effect has erupted.Considering these factors,we made an effort to review most of the articles published on the hydrogen spillover effect and carefully analyzed the aspect of material fabrication.All of our attention has been directed toward the molecular pathway that leads to improve hydrogen evolution reactions performance.In addition,we have attempted to elucidate the spillover paths through the utilization of DFT calculations.Furthermore,we provide some preliminary research suggestions and highlight the opportunities and obstacles that are still to be confronted in this study area.
查看更多>>摘要：High-temperature CO2 electrolysis via solid oxide electrolysis cells(CO2-SOECs)has drawn special attention due to the high energy convention efficiency,fast electrode kinetics,and great potential in carbon cycling.However,the development of cathode materials with high catalytic activity and chemical stability for pure CO2 electrolysis is still a great challenge.In this work,A-site cation deficient dual-phase material,namely(Pr0.4Ca0.6)xFe0.8Ni0.2O3-δ(PCFN,x=1,0.95,and 0.9),has been designed as the fuel electrode for a pure CO2-SOEC,which presents superior electrochemical performance.Among all these compositions,(Pr0.4Ca0.6)0.95Fe0.8Ni0.2O3-δ(PCFN95)exhibited the lowest polarization resistance of 0.458 Ω cm2 at open-circuit voltage and 800 ℃.The application of PCFN95 as the cathode in a single cell yields an impressive electrolysis current density of 1.76 A cm-2 at 1.5 V and 800 ℃,which is 76％higher than that of single cells with stoichiometric Pr0.4Ca0.6Fe0.8Ni0.2O3-δ(PCFN100)cathode.The effects of A-site deficiency on materials'phase structure and physicochemical properties are also systematically investigated.Such an enhancement in electrochemical performance is attributed to the promotion of effective CO2 adsorption,as well as the improved electrode kinetics resulting from the A-site deficiency.
查看更多>>摘要：Solid oxide electrolysis cells(SOECs),displaying high current density and energy efficiency,have been proven to be an effective technique to electrochemically reduce CO2 into CO.However,the insufficiency of cathode activity and stability is a tricky problem to be addressed for SOECs.Hence,it is urgent to develop suitable cathode materials with excellent catalytic activity and stability for further practical application of SOECs.Herein,a reduced perovskite oxide,Pr0.35Sr0.6Fe0.7Cu0.2Mo0.1O3-δ(PSFCM0.35),is developed as SOECs cathode to electrolyze CO2.After reduction in 10％H2/Ar,Cu and Fe nanoparticles are exsolved from the PSFCM0.35 lattice,resulting in a phase transformation from cubic perovskite to Ruddlesden-Popper(RP)perovskite with more oxygen vacancies.The exsolved metal nanoparticles are tightly attached to the perovskite substrate and afford more active sites to accelerate CO2 adsorption and dissociation on the cathode surface.The significantly strengthened CO2 adsorption capacity obtained after reduction is demonstrated by in situ Fourier transform-infrared(FT-IR)spectra.Symmetric cells with the reduced PSFCM0.35(R-PSFCM0.35)electrode exhibit a low polarization resistance of 0.43 Ω cm2 at 850 ℃.Single electrolysis cells with the R-PSFCM0.35 cathode display an outstanding current density of 2947 mA cm-2 at 850 ℃ and 1.6 V.In addition,the catalytic stability of the R-PSFCM0.35 cathode is also proved by operating at 800 ℃ with an applied constant current density of 600 mA cm-2 for 100 h.
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