查看更多>>摘要：The interfaces of perovskite solar cells(PSCs)are well known to be rich in deep-level carrier traps,which serve as non-radiative recombination centers and limit the open-circuit voltage(Voc)and power conversion efficiency(PCE)of PSCs.Defect chemistry and surface passivators have been researched extensively and mainly focused on the neutralization of uncoordinated lead or anion defects.Herein,a novel brominated passivator 2-bromophenethylammonium iodide(2-Br-PEAI)is introduced for a multi-functional passivation effect at the perovskite interface.The brominated species readily form 2D perovskite on top of the 3D perovskite and multi-interact with the 3D perovskite surface.Apart from the halide vacancy filling and anion bonding ability,the Br atoms on the benzene ring can interact with the FA cations via strong hydrogen bonding N-H … Br and interact with the[Pbl6]4-inorganic framework.The interface defects in the PSCs are well passivated,minimizing non-radiative recombination and enhancing device performance.As a result,a champion PCE of 24.22％was achieved with high Voc and fill factor.In addition,modified devices also showed enhanced operational stability(retention of＞95％initial PCE after 400 h)and humidity resistance(＞90％initial PCE maintained after 1500 h under～50％RH).
查看更多>>摘要：SnSe has attracted extensive attention due to its ultralow thermal conductivity and excellent thermoelectric properties.In this work,pressure-induced thermoelectric properties of Pnma SnSe are investigated via first-principles calculations.We uncover distinct energy isosurfaces topology transition of conduction band by applying pressure.The newly created conduction band valley caused by pressure has a distinct anisotropic shape compared to the old one.Inducing pressure can greatly enhance the anisotropy of electronic transport properties of the n-type Pnma SnSe.Furthermore,the lattice thermal conductivity also exhibits anisotropic behavior under pressure due to a special collaged phonon mode.The pressure-induced lattice thermal conductivity along the a-axis shows a slower growth trend than that along the b-axis and c-axis.The optimal ZT value of the n-type Pnma SnSe along the a-axis can reach 1.64 at room temperature.These results would be helpful for designing the Pnma SnSe-based materials for the potential thermoelectric and valleytronic applications.
查看更多>>摘要：Inorganic metal oxide electrochromic materials have good application prospects for energy-saving windows in buildings and smart display applications.Therefore,the development of electrochromic films with good cycling stabilities,fast color-change response times,and high coloring efficiencies has attracted considerable attention.In this study,nanoflake Li-doped NiO electrochromic films were prepared using a hydrothermal method,and the films exhibited superior electrochromic performances in the LiOH electrolyte.Li+ions doping increased the ion transmission rates of the NiO films,and effectively promoted the transportation of ions from the electrolyte into NiO films.Meanwhile,the nanoflake microstructure caused the NiO films to have larger specific surface areas,providing more active sites for electrochemical reactions.It was determined that the NiO-Li20％film exhibited an ultra-fast response in the LiOH electrolyte(coloring and bleaching times reached 3 and 1.5 s,respectively).Additionally,the coloration efficiency was 62.1 cm2 C-1,and good cycling stability was maintained beyond 1500 cycles.Finally,the simulation calculation results showed that Li doping weakened the adsorption strengths of the NiO films to OH-,which reduced the generation and decomposition of NiOOH and helped to improve the cycling stabilities of the films.Therefore,the research presented in this article provides a strategy for designing electrochromic materials in the future.
查看更多>>摘要：One of the major problems limiting the applications of electric double-layer(EDLC)supercapacitor devices is their inability to maintain their cell voltage over a significant period.Self-discharge is a spontaneous decay in charged energy,often resulting in fully depleted devices in a matter of hours.Here,a new method for suppressing this self-discharge phenomenon is proposed by using directionally polarized piezoelectric electrospun nanofiber films as separator materials.Tailored engineering of polyvinylidene fluoride(PVDF)nanofiber films containing a small concentration of sodium dodecyl sulfate(SDS)results in a high proportion of polar β phases,reaching 38±0.5％of the total material.Inducing polarity into the separator material provides a reverse-diode mechanism in the device,such that it drops from an initial voltage of 1.6 down to 1 V after 10 h,as opposed to 0.3 V with a nonpolarized,commercial separator material.Thus,the energy retained for the polarized separator is 37％and 4％for the nonpolarized separator,making supercapacitors a more attractive solution for long-term energy storage.
查看更多>>摘要：The recovery and utilization of carbon dioxide(CO2)is the key to achieve the targets of peak carbon dioxide emissions and carbon neutrality.The Na-CO2 battery made with cheap alkali metal sodium and greenhouse gas CO2 is an effective strategy to consume CO2 and store clean renewable energy.However,the liquid electrolyte volatilization in the open battery system and inevitable dendrite growth restrict the application of Na-CO2 batteries.In this work,magnesium-doped Na3Zr2Si2PO12(NZSP)was studied as a solid electrolyte for solid-state Na-CO2 batteries.The ionic conductivity of Na3.2Zr1.9Mg0.1Si2PO12 reaches 1.16 mS cm-1 at room temperature by replacing Zr ions in Na3Zr2Si2PO12 with Mg ions,and the structural changes are analyzed by neutron powder diffraction.The composite electrolyte consisting of highly conductive Na3.2Zr1.9Mg0.1Si2PO12 and high processability poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)is utilized for the first time to assemble a solid-state Na-CO2 battery.The cell shows a full discharge capacity of 7720 mAh g-1 at 200 mA g-1.The middle gap voltage is lower than 2 V after 120 cycles at 200 mA g-1 and at a cut-off capacity of 500 mAh g-1.This work demonstrates a promising strategy to design high-performance solid-state Na-CO2 batteries.
查看更多>>摘要：Van der Waals(VDW)heterojunctions in a 2D/2D contact provide the highest area for the separation and transfer of charge carriers.In this work,a top-down strategy with a gas erosion process was employed to fabricate a 2D/2D carbon nitride VDW heterojunction in carbon nitride(g-C3N4)with carbon-rich carbon nitride.The created 2D semiconducting channel in the VDW structure exhibits enhanced electric field exposure and radiation absorption,which facilitates the separation of the charge carriers and their mobility.Consequently,compared with bulk g-C3N4 and its nanosheets,the photocatalytic performance of the fabricated carbon nitride VDW heterojunction in the water splitting reaction to hydrogen is improved by 8.6 and 3.3 times,respectively,while maintaining satisfactory photo-stability.Mechanistically,the finite element method(FEM)was employed to evaluate and clarify the contributions of the formation of VDW heterojunction to enhanced photocatalysis,in agreement quantitatively with experimental ones.This study provides a new and effective strategy for the modification and more insights to performance improvement on polymeric semiconductors in photocatalysis and energy conversion.
查看更多>>摘要：Succinonitrile-based plastic crystal electrolytes have emerged for high-energy-density Li metal batteries in terms of their superior ambient ionic conductivity,low flammability,and benign compatibility with high voltage cathode,but are hampered by inherent instabilities toward Li anodes.Constructing hierarchical solid electrolytes structure is a fundamental approach to protect Li anode from succinonitrile attacks,with succinonitrile-based oxidation-resistance layer facing high voltage cathode and reduction-tolerant layer contacting Li anode.However,free succinonitrile molecules in succinonitrile-based electrolyte layer can diffuse across the electrolyte/electrolyte interface and further reach Li anode surface during the battery cycle.This chemical"crosstalk"cause reduction-tolerant electrolyte layer to fail to protect the Li anode from the attacks of free succinonitrile molecules.Nano Li6.4La3Zr1.4Ta0.6O12 is introduced creatively into succinonitrile-based electrolyte layer.By taking advantage of the complexation between La atoms in Li6.4La3Zr1.4Ta0.6O12 and N atoms in succinonitrile,the free succinonitrile molecules are successfully immobilized in succinonitrile-based electrolyte layer.The resulting low resistance and highly durable solid electrolyte interphase and cathode electrolyte interphase endow NCM622||Li batteries with remarkable cycle stability.Our research provides a new idea for the real application of plastic crystal electrolytes in high voltage solid-state lithium metal batteries.
查看更多>>摘要：Self-standing carbon-based substrates with satisfied structural stability and property adjustability have promising applications in flexible lithium(Li)metal batteries(FLMBs).Current strategies for modifying carbon materials are normally carried out on powder carbon,and very few of them are suitable for self-standing carbon substrates.Herein,a pore-forming strategy based on the redox chemistry of metallic oxide nanodots is developed to prepare two porous carbon substrates for anode and cathode.Starting with cotton cloth,the resulting hollow carbon fibers substrate with nanopores effectively prevents from Li dendrites formation and large volume change in lithium metal anode(LMA).Simulations indicate that the porous structure leads to homogeneous ion flux,Li-ion concentration,and electric field during Li deposition.Li symmetrical cell based on this substrate remains stable for 8300 h with an ultralow voltage hysteresis of 9 mV.Via a similar route,porous carbon cloth substrate is obtained for subsequently seeding V2O5 nanowires to prepare the cathode.The assembled FLMBs pouch cell delivers a capacity of 8.2 mAh with a high capacity retention of-100％even under dramatic deformation.The demonstrated strategy has far-reaching potential in preparing free-standing porous carbon-based materials for flexible energy storage devices.
查看更多>>摘要：High energy density and low cost made lithium-sulfur(Li-S)batteries appealing for the next-generation energy storage devices.However,their commercial viability is seriously challenged by serious polysulfide shuttle effect,sluggish sulfur kinetics,and uncontrollable dendritic Li growth.Herein,a dual-functional electrolyte additive,diphenyl ditelluride(DPDTe)is reported for Li-S battery.For sulfur cathodes,DPDTe works as a redox mediator to accelerate redox kinetics of sulfur,in which Te radical-mediated catalytic cycle at the solid-liquid interface contributes significantly to the whole process.For lithium anodes,DPDTe can react with lithium metal to form a smooth and stable organic-inorganic hybrid solid-electrolyte interphase(SEI),enabling homogeneous lithium deposition for suppressing dendrite growth.Consequently,the Li-S battery with DPDTe exhibits remarkable cycling stability and superb rate capability,with a high capacity up to 1227.3 mAh g-1 and stable cycling over 300 cycles.Moreover,a Li-S pouch cell with DPDTe is evaluated as the proof of concept.This work demonstrates that organotelluride compounds can be used as functional electrolyte additives and offers new insights and opportunities for practical Li-S batteries.
查看更多>>摘要：In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,which employs alumina as the inorganic reinforcing material and is loaded with polymerization initiator aluminum trifluoromethanesulfonate.Based upon this,a separator-induced in situ directional polymerization technique is demonstrated,and the extra addition of initiators into liquid precursors is no longer required.The polymerization starts from the surface and interior of the separator and extends outward with the gradually dissolving of initiators into the precursor.Compared with its traditional counterpart,the separator-induced poly(1,3-dioxolane)electrolyte shows improved interfacial contact as well as appropriately mitigated polymerization rate,which are conducive to practical applications.Electrochemical measurement results show that the prepared poly(1,3-dioxolane)solid electrolyte possesses an oxidation potential up to 4.4 V and a high Li+transference number of 0.72.After 1000 cycles at 2 C rate(340 mA g-1),the assembled LillLiFePO4 solid battery possesses a 106.8 mAh g-1 discharge capacity retention and 83.5％capacity retention ratio,with high average Coulombic efficiency of 99.5％achieved.Our work may provide new ideas for the design and application of in situ polymerization technique for solid electrolytes and solid batteries.
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