查看更多>>摘要：The development of perovskite photoelectric devices with excellent performance is largely dependent on the defects in the perovskite films.To address this issue,a specific drug,leflunomide(LF,C12H9F3N2O2),was incorporated into the perovskite to reduce defects and improve its photoelectric properties.It is believed that the C=O bond on LF molecule can interact with the uncoordinated Pb2+of the perovskite,thereby reducing non-radiative recombination.This novel approach of incorporating LF into perovskite films has the potential to revolutionize the development of high-performance perovskite photoelectric devices.The trifluoromethyl functional(-CF3)group on LF can form a protective layer on the surface of the perovskite film,shielding it from water erosion.Moreover,LF can be utilized to alter the nucleation position of perovskite,thus minimizing the number of defects and optimizing the film quality.Consequently,the LF-doped perovskite film displays low trap density and high photoelectric performance.The LF-doped perovskite film showed a trap density of 8.28 × 1011,which is notably lower than the 2.04 × 1012 of the perovskite film without LF.The responsivity and detectivity of the LF-doped perovskite photodetector were 0.771 A/W and 2.81 × 1011 Jones,respectively,which are much higher than the 0.23 A/W and 1.06 × 1010 Jones of the LF-undoped perovskite photodetector.Meanwhile,the LF-doped photodetector maintained an initial photocurrent of 86％after 30 days of storage in air,indicating drastically increased environmental stability.This strongly suggests that LF is an effective additive for perovskites utilized in optoelectronic devices with high performance.
查看更多>>摘要：Lithium metal batteries(LMBs)show great promise for achieving energy densities over 400 Wh·kg-1.However,highly flammable organic electrolytes are a long-lasting problem that triggers safety hazards and hinders the commercial application of LMBs.Here,a nonflammable diluted highly concentrated electrolyte(DHCE)with ethoxy(pentafluoro)cyclotriphosphazene(PFPN)as a diluent is developed to simultaneously achieve high safety and cycling stability of high-voltage LMBs.The optimal DHCE not only ensures reversible Li deposition/dissolution behavior with a superior average Coulombic efficiency(CE)over 99.1％on lithium metal anode(LMA),but also suppresses side reactions and stress crack on the LiCoO2(LCO)under high cut-off voltage.The newly developed DHCE exhibits high thermal stability,showing complete nonflammability and reduced heat generation between the electrolyte and delithiated LCO/cycled LMA.This work offers an opportunity for rational designing nonflammable electrolytes toward high-voltage and safe LMBs.
查看更多>>摘要：Aqueous rechargeable batteries are the promising energy storge technology due to their safety,low cost,and environmental friendliness.Ammonium ion(NH4+)is an ideal charge carrier for such batteries because of its small hydration radius and low molar mass.In this study,VO2·xH2O with rich oxygen defects(d-HVO)is designed and synthesized,and it exhibits unique nanoarray structure and good electrochemical performances for NH4+storge.Experimental and calculation results indicate that oxygen defects in d-HVO can enhance the conductivity and diffusion rate of NH4+,leading to improved electrochemical performances.The most significant improvement is observed in d-HVO with 2 mmol thiourea(d-HVO-2)(220 mAh·g-1at 0.1 A·g-1),which has a moderate defect content.A full cell is assembled using d-HVO-2 as the anode and polyaniline(PANI)as the cathode,which shows excellent cycling stability with a capacity retention rate of 80％after 1000 cycles and outstanding power density up to 4540 W·kg-1.Moreover,the flexible d-HVO-2‖PANI battery,based on quasi-solid electrolyte,shows excellent flexibility under different bending conditions.This study provides a new approach for designing and developing high-performance NH4+storage electrode materials.
查看更多>>摘要：New generation of lithium-ion batteries(LIBs)integrating solar energy conversion and storage is emerging,as they could solve the fluctuation problem in the utilization of solar energy.Photo-rechargeable lithium-ion batteries(PR-LIBs)are ideal devices for such target,in which solar energy is converted into electricity and stored in LIB.In order to achieve the high performance of PR-LIB,it is crucial to develop dual-function electrode materials that can synergistically capture solar energy and store lithium.Herein,we present photo-rechargeable lithium-ion batteries using defective black TiO2 as photoanode prepared by lithium reduction.The photoanode exhibits excellent photo response in full solar spectrum with a capacity enhancement of 46.4％under illumination,corresponding to the energy conversion efficiency of 4.4％at the current density of 1 A·g-1.When illumination is applied at 20 mA·g-1,the battery capacity increases from～230 in dark to～349 mAh·g-1 at the first cycle,and then stabilizes at 310 mAh·g-1,approaching the theoretical value of 335 mAh·g-1 of TiO2 electrode material.This finding provides thoughts for breaking the capacity limitations in TiO2 and paves the way for powering LIBs by solar illumination.
查看更多>>摘要：In order to enhance the ionic conductivity of solid polymer electrolytes(SPEs)and their structural rigidity against lithium dendrite during lithium-ion battery(LIB)cycling,we propose porous garnet Li64La3Zr2Al0.2O12(LLZO),as the filler to SPEs.The porous LLZO with interlinked grains was synthesized via a resol-assisted cationic coordinative co-assembly approach.The porous structure of LLZO with high specific surface area facilitates the interaction between polymer and filler and provides sufficient entrance for Li+migration into the LLZO phase.Furthermore,the interconnection of LLZO grains forms continuous inorganic pathways for fast Li+migration,which avoid the multiple diffusion for Li+in interface.As a result,the SPEs with porous LLZO(SPE-PL)show a high ionic conductive of 0.73 mS·cm-1 at 30 ℃ and lithium-ion transference number of 0.40.The porous LLZO with uniformly dispersed pores also acts as an ion distributor to regulate ionic flux.The lithium-symmetrical batteries assembled with SPE-PL show a highly stable Li plating/stripping cycling for nearly 3000 h at 0.1 mA·cm-2.The corresponding Li/LiFePO4 batteries also exhibit excellent cyclic performance with capacity retention of 75％after nearly 500 cycles.This work brings new insights into the design of conductive fillers and the optimization of SPEs.
查看更多>>摘要：Spinel LiNi0.5-xMn1.5+xO4(LNMO)has attracted intensive interest for lithium-ion battery due to its high voltage and high energy density.However,severe capacity fade attributed to unstable surface structure has hampered its commercialization.Oxygen vacancies(OVs)tend to occur in the surface of the material and lead to surface structure reconstruction,which deteriorates the battery performance during electrochemical cycling.Here,we utilize high-temperature-shock(HTS)method to synthesize LNMO materials with fewer surface OVs.Rapid calcination drives lower surface OVs concentration,reducing the content of Mn3+and surface reconstruction layers,which is beneficial to obtain a stable crystal structure.The LNMO material synthesized by HTS method delivers an initial capacity of 127 mAh·g-1 at 0.1 C and capacity retention of 81.6％after 300 cycles at 1 C,and exhibits excellent performance at low temperature.
查看更多>>摘要：As a promising candidate for the next generation energy storage system,rechargeable lithium-oxygen batteries(LOBs)still face substantial challenges caused by insulating discharge products that preclude their practical application.Exploring highly efficient cathode catalysts capable of facilitating formation/decomposition of discharge products is considered as an essential approach towards high performance LOBs.Herein,Pd decorated Te nanowires(Pd@Te NWs)were synthesized as advanced catalyst in LOBs to maximize Pd utilization and achieve synergistic effect,in which Pd clusters were uniformly grown on Te substrate though regulating the Pd:Te ratio.Meanwhile,Pd@Te nanowires assembled into an interpenetrating network-like structure by vacuum filtration and employed as flexible cathode,enabling LOBs achieved an ultralong 190 cycles stability and a superior specific capacity of 3.35 mAh·cm-2.Experimental studies and density functional theory(DFT)calculations reveal the excellent catalytic ability of Pd@Te and synergistic catalytic mechanism of Pd and Te,in which uniform electron distribution,extensive electron exchange,and large adsorption distance between Pd cluster and discharge products promote homogeneous adsorption/desorption of discharge products,while the high adsorption energy of Te substrate for Li species reduces the initial dynamical energy barrier during discharging process.The current work provides viable strategy to design composite catalysts for flexible cathode of LOBs with synergistic catalytic effects.
查看更多>>摘要：All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong safety.However,the interface issues,including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes,have restricted the development of high-voltage ASSLBs.Herein,we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li6.4La3Zr1.4Ta0.6O12(LLZTO)-cathode interfaces.The polymer can perfectly fill the voids and create a stable interface contact between LLZTO and cathodes.In addition,the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte(SPE),which facilitates the electrochemical stability with high-voltage cathode.The all-solid-state Li|LLZTO-SPE|LiFe0.4Mn0.6PO4(LMFP)cells achieve a low interface impedance,high specific capacity,and excellent cycling performance.This work presents an effective and practical strategy to rationally design the electrode-electrolyte interface for the application of high-voltage ASSLBs.
查看更多>>摘要：Nanostructured silicon anodes have shown extraordinary lithium storage properties for lithium-ion batteries(LIBs)but are usually achieved at low areal loadings(＜1.5 mg·cm-2)with low areal capacity.Sustaining sound electrochemical performance at high loading requires proportionally higher ion/electron currents and robust structural stability in the thicker electrode.Herein,we report a three-dimensional(3D)printed silicon-graphene-carbon nanotube(3D-Si/G/C)electrode for simultaneously achieving ultrahigh areal/gravimetric capacities at high mass loading.The periodically arranged vertical channels and hierarchically porous filaments facilitate sufficient electrolyte infiltration and rapid ion diffusion,and the carbonaceous network provides excellent electron transport properties and mechanical integrity,thus endowing the printed 3D-Si/G/C electrode with fast electrochemical reaction kinetics and reversibility at high mass loading.Consequently,the 3D-Si/G/C with high areal mass loading of 12.9 mg·cm-2 exhibits excellent areal capacity of 12.8 mAh·cm-2 and specific capacity of 1007 mAh·g-1,respectively.In-situ optical microscope and ex-situ scanning electron microscope(SEM)confirm that the hierarchically porous filaments with interconnected carbon skeletons effectively suppress the volume change of silicon and maintain stable micro-lattice architecture.A 3D printed 3D-Si/G/C-1 ‖3D-LiFePO4/G full cell holds excellent cyclic stability(capacity retention rate of 78％after 50 cycles)with an initial Coulombic efficiency(ICE)of 96％.This work validates the feasibility of 3D printing on constructing high mass loading silicon anode for practical high energy-density LIBs.
查看更多>>摘要：The outstanding advantages of lightweight and flexibility enable flexible perovskite solar cells(PSCs)to have great application potential in mobile energy devices.Due to the low cost,low-temperature processibility,and high electron mobility,SnO2 nanocrystals have been widely employed as the electron transport layer in flexible PSCs.To prepare high-quality SnO2 layers,a monodispersed nanocrystal solution is normally used.However,the SnO2 nanocrystals can easily aggregate,especially after long periods of storage.Herein,we develop a green and cost-effective strategy for the synthesis of high-quality SnO2 nanocrystals at low temperatures by introducing small molecules of glycerol,obtaining a stable and well-dispersed SnO2-nanocrystal isopropanol dispersion successfully.Due to the enhanced dispersity and super wettability of this alcohol-based SnO2-nanocrystal solution,large-area smooth and dense SnO2 films are easily deposited on the plastic conductive substrate.Furthermore,this contributes to effective charge transfer and suppressed non-radiative recombination at the interface between the SnO2 and perovskite layers.As a result,a greatly enhanced power conversion efficiency(PCE)of 21.8％from 19.2％is achieved for small-area flexible PSCs.A large-area 5 cm × 5 cm flexible perovskite solar mini-module with a champion PCE of 16.5％and good stability is also demonstrated via this glycerol-modified SnO2-nanocrystal isopropanol dispersion approach.
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