查看更多>>摘要：Crystallization process determines the quality of perovskite films and the performances of resultant per-ovskite solar cells(PSCs).Dimethylamine oxalate has been proven as a multifunctional modulator,and is explored as an efficient additive in manipulating the crystallization process of CsPbl3 perovskite films.On one hand,oxalate serves as the precipitator that facilitates the nucleation process of intermediate.The larger size of intermediate is conductive to the larger size and smaller grain boundaries of resultant per-ovskite.On the other hand,in subsequent annealing process,the phase conversion and growth process of transient perovskite can be decelerated due to the strong interactions of oxalate with both dimethy-lamine cation(DMA+)and Pb2+.Due to the optimized crystallization kinetics,the morphology and quality of CsPbl3 perovskite films are comprehensively improved with lower defect concentrations,and charge recombination loss is effectively suppressed.Benefiting from the optimized crystal quality of perovskite films,the carbon electrode-based CsPbI3 PSCs exhibit a champion efficiency of 18.48％.This represents one of the highest levels among all hole transport layer-free inorganic perovskite solar cells.
查看更多>>摘要：As a prevailing cathode material of lithium-ion batteries(LIBs),LiCoO2(LCO)still encounters the tricky problems of structural collapse,whose morphological engineering and cation doping are crucial for sur-mounting the mechanical strains and alleviating phase degradation upon cycling.Hereinafter,we pro-pose a strategy using a zeolitic imidazolate framework(ZIF)as the self-sacrificing template to directionally prepare a series of LiNi0.1Co0.9O2(LNCO)with tailorable electrochemical properties.The rational selection of sintering temperature imparts the superiority of the resultant products in lithium storage,during which the sample prepared at 700 ℃(LNCO-700)outperforms its counterparts in cycla-bility(156.8 mA h g-1 at 1 C for 200 cycles in half cells,1 C=275 mA g-1)and rate capability due to the expedited ion/electron transport and the strengthen mechanical robustness.The feasibility of proper Ni doping is also divulged by half/full cell tests and theoretical study,during which LNCO-700(167 mA h g-1 at 1 C for 100 cycles in full cells)surpasses LCO-700 in battery performance due to the mitigated phase deterioration,stabilized layered structure,ameliorated electronic conductivity,and exalted lithium stor-age activity.This work systematically unveils tailorable electrochemical behaviors of LNCO to better direct their practical application.
查看更多>>摘要：Abundant interfacial defects remain a significant challenge that hampers both the efficiency and stability of perovskite solar cells(PSCs).Herein,an alcohol-dispersed conducting polymer complex,denoted as PEDOT:F(Poly(3,4-ethylene dioxythiophene):Perfluorinated sulfonic acid ionomers),is introduced into the interface between perovskite and hole transporting layer in regular-structured PSCs.PEDOT:F serves as a multi-functional interface layer(filling grain boundaries and covering perovskite's grain-surface)to achieve a robust interaction with organic groups within perovskites,which could induce a structural transformation of PEDOT to increase its conductivity for the efficient hole-transport.Furthermore,the strong interaction between PEDOT and perovskites could promote an effective coupling of undercoordi-nated Pb2+ions with the lone electron pairs near O & S atoms in PEDOT molecules,thereby enhancing defect passivation.Additionally,PEDOT:F with inherent hydrophobic properties prevents effectively moisture invasion into perovskites for the improved long-term stability of the PSCs.Consequently,the PEDOT:F-based PSCs achieved a champion efficiency of 24.81％,and maintained ca.92％of their initial efficiency after 7680 h of storage in a dry air environment,accompanied by the enhanced photothermal stability.
查看更多>>摘要：Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries,their widespread commercial adoption is still hindered by significant volume expansion during cycling,especially at high active mass loadings crucial for practical use.The root of these challenges lies in the mechanical instabil-ity of the material,which subsequently leads to the structural failure of the electrode.Here,we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles.This composite features a unique interlayer-bonded graphite structure,achieved through the application of a modified spark plasma sintering method.Notably,this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength(Vickers hardness:up to 658 MPa,Young's modulus:11.6 GPa).This strength effectively accommodates silicon expansion,result-ing in an impressive areal capacity of 2.9 mA h cm-2(736 mA h g-1)and a steady cycle life(93％after 100 cycles).Such outstanding performance is paired with features appropriate for large-scale industrial pro-duction of silicon batteries,such as active mass loading of at least 3.9 mg cm-2,a high-tap density elec-trode material of 1.68 g cm-3(secondary clusters:1.12 g cm-3),and a production yield of up to 1 kg per day.
查看更多>>摘要：Since the advent of the solid-state batteries,employing solid polymer electrolytes(SPEs)to replace rou-tine flammable liquid electrolytes is regarded to be one of the most promising solutions in pursing high-energy-density battery systems.SPEs with superior thermal stability,good processability,and high mechanical modulus obtain increasing attentions.However,SPE-based batteries are not impenetrable due to their decomposition and combustibility under extreme conditions.Researchers believe incorporat-ing appropriate flame-retardant additives/solvents/fragments into SPEs can intrinsically reduce their flammability to solve the battery safety issues.In this review,the recent research progress of incom-bustible SPEs,with special emphasis on flame-retardant structural design,is summarized.Specifically,a brief introduction of flame-retardant mechanism,evaluation index for safety of SPEs,and a detailed overview of the latest advances on diverse-types SPEs in various battery systems are highlighted.The deep insight into thermal runaway process,the free-standing incombustible GPEs,and the rational design of pouch cell structures may be the main directions to motivate revolutionary next-generation for safety batteries.
查看更多>>摘要：Composite Li metal anodes based on three-dimensional(3D)porous frameworks have been considered as an effective material for achieving stable Li metal batteries with high energy density.However,uneven Li deposition behavior still occurs at the top of 3D frameworks owing to the local accumulation of Li ions.To promote uniform Li deposition without top dendrite growth,herein,a layered multifunctional framework based on oxidation-treated polyacrylonitrile(OPAN)and metal-organic framework(MOF)derivatives was proposed for rationally regulating the distribution of Li ions flux,nucleation sites,and electrical con-ductivity.Profiting from these merits,the OPAN/carbon nano fiber-MOF(CMOF)composite framework demonstrated a reversible Li plating/stripping behavior for 500 cycles with a stable Coulombic efficiency of around 99.0％at the current density of 2 mA/cm2.Besides,such a Li composite anode exhibited a supe-rior cycle lifespan of over 1300 h under a low polarized voltage of 18 mV in symmetrical cells.When the Li composite anode was paired with LiFePO4(LFP)cathode,the obtained full cell exhibited a stable cycling over 500 cycles.Moreover,the COMSOL Multiphysics simulation was conducted to reveal the effects on homogeneous Li ions distribution derived from the above-mentioned OPAN/CMOF framework and elec-trical insulation/conduction design.These electrochemical and simulated results shed light on the diffi-culties of designing stable and safe Li metal anode via optimizing the 3D frameworks.
查看更多>>摘要：Urea generation through electrochemical CO2 and NO3-co-reduction reaction(CO2NO3RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu2(OH)2CO3)as an efficient CO2NO3RR electrocatalyst with an impressive urea Faradaic efficiency of 45.2％+2.1％and a high yield rate of 1564.5±145.2 μg h-1 mgcat-1.More importantly,H2 evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu2(OH)2CO3 by combining the two intermediates,*COOH and*NHO.This work demon-strates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO2NO3RR,and provide guidance for rational design of more advanced catalysts.
查看更多>>摘要：Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working per-formance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following elec-trochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li+at high and low potentials,respectively.Such preferential adsorption suggests that N-doped graphite can promote Li+desolvation and regulate the location of Li+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.
查看更多>>摘要：Aqueous potassium-ion batteries(APIBs),recognized as safe and reliable new energy devices,are consid-ered as one of the alternatives to traditional batteries.Layered MnO2,serving as the main cathode,exhi-bits 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 MnO2 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 den-sity of 0.1 A g-1.maintaining a capacity retention rate of＞90％after 5000 cycles at 5 A g-1.In-situ and ex-situ characterization techniques revealed the energy-storage mechanism of KMO@rGO:layered MnO2 traps a large amount of"dead"water molecules during K+ions removal.However,the introduction of gra-phene 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 MnO2.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 MnO2 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.
查看更多>>摘要：Bromine has attracted significant attention as a cathode material for aqueous batteries due to its high reduction potential of 1.05 V(Br-3+2e-↔ 3Br-),impressive theoretical specific capacity of 223 mA h g-1,and rapid reaction kinetics in the electrolyte.However,searching for compatible anode materials to match with bromine has posed a challenge due to its highly corrosive nature.In this study,we developed oxygen-deficient MoO3 with TiO2 coating(referred to as MoO3-x@TiO2)as an anode mate-rial to pair with a bromine cathode in static full batteries.The oxygen deficiency contributes to enhanced electronic and protonic diffusion within the MoO3-x lattice,while the TiO2 coating mitigates structural dissolution and proton trapping during cycling.The MoO3-x@TiO2 demonstrates fast charge storage kinetics and excellent resistance to bromine corrosion.The impressive compatibility between MoO3-x@TiO2 and bromine enables the construction of membrane-less full batteries with exceptional rate capability and cyclic stability.The MoO3-x@TiO2-bromine battery achieves an energy density of 70.8 W h kg-1 at a power density of 328.1 W kg-1,showcasing an impressive long-term cyclic life of 20,000 cycles.Our study provides valuable insights for the development of high-performance aqueous secondary batteries.
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