Rate capability,peak power,and energy density are of vital importance for the capacitive energy storage(CES)of electrochemical energy devices.The frequency response analysis(FRA)is regarded as an efficient tool in stu...Rate capability,peak power,and energy density are of vital importance for the capacitive energy storage(CES)of electrochemical energy devices.The frequency response analysis(FRA)is regarded as an efficient tool in studying the CES.In the present work,a bi-scale impedance transmission line model(TLM)is firstly developed for a single pore to a porous electrode.Not only the TLM of the single pore is reparameterized but also the particle packing compactness is defined in the bi-scale.Subsequently,the CES properties are identified by FRA,focused on rate capability vs.characteristic frequency,peak power vs.equivalent series resistance,and energy density vs.low frequency limiting capacitance for a single pore to a porous electrode.Based on these relationships,the CES properties are numerically simulated and theoretically predicted for a single pore to a porous electrode in terms of intra-particle pore length,intra-particle pore diameter,inter-particle pore diameter,electrolyte conductivity,interfacial capacitance&exponent factor,electrode thickness,electrode apparent surface area,and particle packing compactness.Finally,the experimental diagnosis of four supercapacitors(SCs)with different electrode thicknesses is conducted for validating the bi-scale TLM and gaining an insight into the CES properties for a porous electrode to a single pore.The calculating results suggest,to some extent,the inter-particle pore plays a more critical role than the intra-particle pore in the CES properties such as the rate capability and the peak power density for a single pore to a porous electrode.Hence,in order to design a better porous electrode,more attention should be given to the inter-particle pore.展开更多
Pure and noble metal(Pt,Pd,and Au)doped TiO_(2)nanoceramics have been prepared from TiO_(2)nanoparticles through traditional pressing and sintering.For those samples sintered at 550℃,a typical premature sintering occ...Pure and noble metal(Pt,Pd,and Au)doped TiO_(2)nanoceramics have been prepared from TiO_(2)nanoparticles through traditional pressing and sintering.For those samples sintered at 550℃,a typical premature sintering occurred,which led to the formation of a highly porous microstructure with a Brunauer-Emmett-Teller(BET)specific surface area of 23 m^(2)/g.At room temperature,only Pt-doped samples showed obvious response to hydrogen,with sensitivities as high as~500 for 1000 ppm H_(2)in N_(2);at 300℃,all samples showed obvious responses to CO,while the responses of noble metal doped samples were much higher than that of the undoped ones.The mechanism for the observed sensing capabilities has been discussed,in which the catalytic effect of Pt for hydrogen is believed responsible for the room-temperature hydrogen sensing capabilities,and the absence of glass frit as commonly used in commercial thick-film metal oxide gas sensors is related to the high sensitivities.It is proposed that much attention should be paid to metal oxide porous nanoceramics in developing gas sensors with high sensitivities and low working temperatures.展开更多
PbTiO_(3)nanorods with tetragonal phase were synthesized by hydrothermal method and heat treatment,and temperature-dependent electrical transport properties of individual PbTiO_(3)nanorod were investigated.The results...PbTiO_(3)nanorods with tetragonal phase were synthesized by hydrothermal method and heat treatment,and temperature-dependent electrical transport properties of individual PbTiO_(3)nanorod were investigated.The results show that the conductivities of PbTiO_(3)nanorods are gradually enhanced with temperature increasing from 77.4 to 295 K,and exhibit the typical nonlinear Ⅰ–Ⅴ char-acteristics.The barrier height between Au electrode and nanorod is reduced from 0.137 to 0.088 eV with increasing bias from 0.2 to 1 V.The corresponding values of thermal activation energies are 0.172 and 0.06 eV below the conduction band for 180–295 and 77.4–180 K,respectively.This semiconductor-like behavior may result from the larger number of surface defects or localized states in the amorphorized PbTiO_(3).展开更多
Hybrid perovskite solar cells(PSCs)have been intensively studied in recent years because of their high efficiency and low costs.For PSCs,the electron transport layer(ETL)is a key for its photoelectric conversion effic...Hybrid perovskite solar cells(PSCs)have been intensively studied in recent years because of their high efficiency and low costs.For PSCs,the electron transport layer(ETL)is a key for its photoelectric conversion efficiency.Here we demonstrate the application of amorphous InGaZnO_(4)thin films as ETL for efficient PSCs by pulsed laser deposition(PLD).The PSC device using such InGaZnO_(4)amorphous film as ETL has achieved an efficiency of 15.1%.The outstanding performance is attributed to the excellent properties of amorphous InGaZnO_(4)oxide thin films,including high electron mobility and high transparency,what is more,the electronic properties of the films can be controlled by changing the partial pressure of oxygen in the deposition chamber and post-deposition annealing process.Our result will be helpful for preparation of large area PSCs and other opto-electric devices at low temperature by physical vapor deposition method.展开更多
基金financial support from the National Science Foundation of China(22078190)the National Key R&D Plan of China(2020YFB1505802)。
文摘Rate capability,peak power,and energy density are of vital importance for the capacitive energy storage(CES)of electrochemical energy devices.The frequency response analysis(FRA)is regarded as an efficient tool in studying the CES.In the present work,a bi-scale impedance transmission line model(TLM)is firstly developed for a single pore to a porous electrode.Not only the TLM of the single pore is reparameterized but also the particle packing compactness is defined in the bi-scale.Subsequently,the CES properties are identified by FRA,focused on rate capability vs.characteristic frequency,peak power vs.equivalent series resistance,and energy density vs.low frequency limiting capacitance for a single pore to a porous electrode.Based on these relationships,the CES properties are numerically simulated and theoretically predicted for a single pore to a porous electrode in terms of intra-particle pore length,intra-particle pore diameter,inter-particle pore diameter,electrolyte conductivity,interfacial capacitance&exponent factor,electrode thickness,electrode apparent surface area,and particle packing compactness.Finally,the experimental diagnosis of four supercapacitors(SCs)with different electrode thicknesses is conducted for validating the bi-scale TLM and gaining an insight into the CES properties for a porous electrode to a single pore.The calculating results suggest,to some extent,the inter-particle pore plays a more critical role than the intra-particle pore in the CES properties such as the rate capability and the peak power density for a single pore to a porous electrode.Hence,in order to design a better porous electrode,more attention should be given to the inter-particle pore.
基金supported by the National High-tech R&D Program of China(863 Program)(No.2013AA031903)the National Natural Science Foundation of China under Grant Nos.J1210061 and 50772077.
文摘Pure and noble metal(Pt,Pd,and Au)doped TiO_(2)nanoceramics have been prepared from TiO_(2)nanoparticles through traditional pressing and sintering.For those samples sintered at 550℃,a typical premature sintering occurred,which led to the formation of a highly porous microstructure with a Brunauer-Emmett-Teller(BET)specific surface area of 23 m^(2)/g.At room temperature,only Pt-doped samples showed obvious response to hydrogen,with sensitivities as high as~500 for 1000 ppm H_(2)in N_(2);at 300℃,all samples showed obvious responses to CO,while the responses of noble metal doped samples were much higher than that of the undoped ones.The mechanism for the observed sensing capabilities has been discussed,in which the catalytic effect of Pt for hydrogen is believed responsible for the room-temperature hydrogen sensing capabilities,and the absence of glass frit as commonly used in commercial thick-film metal oxide gas sensors is related to the high sensitivities.It is proposed that much attention should be paid to metal oxide porous nanoceramics in developing gas sensors with high sensitivities and low working temperatures.
基金supported by the National Natural Science Foundation of China(NSFC Grant No.61274073).
文摘PbTiO_(3)nanorods with tetragonal phase were synthesized by hydrothermal method and heat treatment,and temperature-dependent electrical transport properties of individual PbTiO_(3)nanorod were investigated.The results show that the conductivities of PbTiO_(3)nanorods are gradually enhanced with temperature increasing from 77.4 to 295 K,and exhibit the typical nonlinear Ⅰ–Ⅴ char-acteristics.The barrier height between Au electrode and nanorod is reduced from 0.137 to 0.088 eV with increasing bias from 0.2 to 1 V.The corresponding values of thermal activation energies are 0.172 and 0.06 eV below the conduction band for 180–295 and 77.4–180 K,respectively.This semiconductor-like behavior may result from the larger number of surface defects or localized states in the amorphorized PbTiO_(3).
基金supported by the National Natural Science Foundation of China(Nos.51972157,11964017)the Jiangxi’s Natural Science Foundation(No.20192ACB21017)the financial support from Hubei Key Laboratory of Ferro and Piezoelectric Materials and Devices(No.K201803).
文摘Hybrid perovskite solar cells(PSCs)have been intensively studied in recent years because of their high efficiency and low costs.For PSCs,the electron transport layer(ETL)is a key for its photoelectric conversion efficiency.Here we demonstrate the application of amorphous InGaZnO_(4)thin films as ETL for efficient PSCs by pulsed laser deposition(PLD).The PSC device using such InGaZnO_(4)amorphous film as ETL has achieved an efficiency of 15.1%.The outstanding performance is attributed to the excellent properties of amorphous InGaZnO_(4)oxide thin films,including high electron mobility and high transparency,what is more,the electronic properties of the films can be controlled by changing the partial pressure of oxygen in the deposition chamber and post-deposition annealing process.Our result will be helpful for preparation of large area PSCs and other opto-electric devices at low temperature by physical vapor deposition method.