用 TEM、SEM、AES 和 x 射线衍射技术研究了铝阳极氧化膜的形态、结构和化学成分分布。试验结果表明,在硫酸中形成的阳极氧化膜和在磷酸和草酸中形成的膜一样,也存在着多孔型和壁垒型两种形态,但其临界电流密度较高。铝阳极氧化膜由过...用 TEM、SEM、AES 和 x 射线衍射技术研究了铝阳极氧化膜的形态、结构和化学成分分布。试验结果表明,在硫酸中形成的阳极氧化膜和在磷酸和草酸中形成的膜一样,也存在着多孔型和壁垒型两种形态,但其临界电流密度较高。铝阳极氧化膜由过剩的铝和 Al_2O_3组成,属非晶态结构,镍盐和锡盐电解着色后非晶态结构和膜中 Al、O 和 S 的分布均无显著改变,而 Sn 和 Ni 则沉积于膜孔底部,但其分布略有不同;着色添加剂的组成物未有明显地进入膜中。展开更多
Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple synthesis.Cycling performance is an important criterion for evaluating the applicat...Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple synthesis.Cycling performance is an important criterion for evaluating the application prospects of batteries.However,facing challenges,including phase transitions,ambient stability,side reactions,and irreversible anionic oxygen activity,the cycling performance of layered oxide cathode materials still cannot meet the application requirements.Therefore,this review proposes several strategies to address these challenges.First,bulk doping is introduced from three aspects:cationic single doping,anionic single doping,and multi-ion doping.Second,homogeneous surface coating and concentration gradient modification are reviewed.In addition,methods such as mixed structure design,particle engineering,high-entropy material construction,and integrated modification are proposed.Finally,a summary and outlook provide a new horizon for developing and modifying layered oxide cathode materials.展开更多
Transparent conductive oxide(TCO)thin films are highly desired as electrodes for modern flat-panel displays and solar cells.Alternative indium-free TCO materials are highly needed,because of the scarcity and the high ...Transparent conductive oxide(TCO)thin films are highly desired as electrodes for modern flat-panel displays and solar cells.Alternative indium-free TCO materials are highly needed,because of the scarcity and the high price of indium.Based on the mechanism of resonant doping,Ta has been identified as an effective dopant for SnO_(2)to achieve highly conductive and transparent TCO.In this work,we fabricated a series of Ta-doped SnO_(2)thin films(Sn_(1-x)Ta_(x)O_(2),x=0.001,0.01,0.02,0.03)with high conductivity and high optical transparency via a low-cost sol-gel spin coating method.The Sn_(0.98)Ta_(0.02)O_(2)film achieves the highest electrical conductivity of 855 S cm-1with a carrier concentration of2.3×10^(20)cm^(-3)and high mobility of 23 cm^(2)V^(-1)s^(-1).The films exhibit a very high optical transparency of 89.5%in the visible light region.High-resolution X-ray photoemission spectroscopy and optical spectroscopy were combined to gain insights into the electronic structure of the Sn_(1-x)Ta_(x)O_(2)films.The optical bandgaps of the films are increased from 3.96 eV for the undoped SnO_(2)to 4.24 eV for the Sn_(0.98)Ta_(0.02)O_(2)film due to the occupation of the bottom of conduction band by free electrons,i.e.,the Burstein-Moss effect.Interestingly,a bandgap shrinkage is also directly observed due to the bandgap renormalization arising from many-body interactions.The double guarantee of transparency and conductivity in Sn_(1-x)Ta_(x)O_(2)films and the low-cost growth method provide a new platform for optoelectronic and solar cell applications.展开更多
The synthesis,structure and thermal behavior of [Y（dbm）3（H2 O）]（3）（dbm = 1,3-diphenyl-1,3-propandionate） and its use as a spin-coating precursor for Y2 O3 deposition is reported. Complex 3 was prepared by the ...The synthesis,structure and thermal behavior of [Y（dbm）3（H2 O）]（3）（dbm = 1,3-diphenyl-1,3-propandionate） and its use as a spin-coating precursor for Y2 O3 deposition is reported. Complex 3 was prepared by the reaction of [Y（NO3）3·6 H2 O]（1） with 3 equiv of Hdbm（2） in presence of NaOH. The molecular structure of 3 in the solid-state was determined by single X-ray crystal diffraction. Both C1 symmetric crystallographically independent species of 3 possess a YO7 coordination setup with minor deviation from an ideal capped octahedron coordination geometry（∧ enantiomer）. Complex 3 forms a1 D chain, due to intermolecular hydrogen bonds between the coordinated H2 O molecule and the 0 atom of the dbm ligand, respectively. The thermal decomposition behavior of 3 was investigated by thermogravimetric studies in the temperature range of 40-800 ℃ and 40-1300 ℃ under an oxygen and argon atmosphere, respectively. Powder X-ray diffraction（PXRD） measurements of the residues confirmed the formation of Y2 O3. Complex 3 was applied as a spin-coating precursor for yttrium oxide film formation on either Si wafers with a continuous 100 nm thick SiO2 film, or with a native oxide layer.The as-deposited Y2 O3 layers are smooth, conformal, dense and transparent and are of a thickness of 27 and 30 nm, respectively.展开更多
Lithium-rich manganese-based material shows great potential as the high specific cathode materials due to its low cost,environmental friendliness,high operating voltage and simple preparation process.However,the poor ...Lithium-rich manganese-based material shows great potential as the high specific cathode materials due to its low cost,environmental friendliness,high operating voltage and simple preparation process.However,the poor capacity retention and cycling performance caused by its unstable structure during cycling restrict the commercialization.In this work,Li_(1.2)Ni_(0.16)Mn_(0.56)Co_(0.08)O_(2)was synthesized utilizing a Coprecipitation method and different amount of La(PO_(3))_(3)(La(PO_(3))_(3)=2 wt%,4 wt%and 6 wt%)was selected as the coating layer to resolve the above issues.During the calcination process,La(PO_(3))_(3)reacts with impurities such as Li OH and Li_(2)CO_(3)on the lithium-rich surface to reduce the residual lithium on the surface,thus improving the interfacial stability,slowing down the corrosion of the electrolyte,and finally enhancing its electrochemical performance.The cathode materials coated with 4%of La(PO_(3))_(3)showed the best electrochemical performance in terms of capacity retention and cycling performance compared to the pristine NCM.The high initial discharge capacity of 214.21 m Ah/g and capacity retention of 94.2%after 100 cycles at 0.1 C can be obtained.This work provides an effective strategy to protect the cathode from corrosion and will promote its further practical applications in high specific Li-ion batteries.展开更多
文摘用 TEM、SEM、AES 和 x 射线衍射技术研究了铝阳极氧化膜的形态、结构和化学成分分布。试验结果表明,在硫酸中形成的阳极氧化膜和在磷酸和草酸中形成的膜一样,也存在着多孔型和壁垒型两种形态,但其临界电流密度较高。铝阳极氧化膜由过剩的铝和 Al_2O_3组成,属非晶态结构,镍盐和锡盐电解着色后非晶态结构和膜中 Al、O 和 S 的分布均无显著改变,而 Sn 和 Ni 则沉积于膜孔底部,但其分布略有不同;着色添加剂的组成物未有明显地进入膜中。
基金the Fundamental Research Funds for the Central Universities,China(No.06500177)the National Natural Science Foundation of China Joint Fund Project(No.U1764255)。
文摘Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple synthesis.Cycling performance is an important criterion for evaluating the application prospects of batteries.However,facing challenges,including phase transitions,ambient stability,side reactions,and irreversible anionic oxygen activity,the cycling performance of layered oxide cathode materials still cannot meet the application requirements.Therefore,this review proposes several strategies to address these challenges.First,bulk doping is introduced from three aspects:cationic single doping,anionic single doping,and multi-ion doping.Second,homogeneous surface coating and concentration gradient modification are reviewed.In addition,methods such as mixed structure design,particle engineering,high-entropy material construction,and integrated modification are proposed.Finally,a summary and outlook provide a new horizon for developing and modifying layered oxide cathode materials.
基金supported by the National Natural Science Foundation of China(21872116 and 22075232)。
文摘Transparent conductive oxide(TCO)thin films are highly desired as electrodes for modern flat-panel displays and solar cells.Alternative indium-free TCO materials are highly needed,because of the scarcity and the high price of indium.Based on the mechanism of resonant doping,Ta has been identified as an effective dopant for SnO_(2)to achieve highly conductive and transparent TCO.In this work,we fabricated a series of Ta-doped SnO_(2)thin films(Sn_(1-x)Ta_(x)O_(2),x=0.001,0.01,0.02,0.03)with high conductivity and high optical transparency via a low-cost sol-gel spin coating method.The Sn_(0.98)Ta_(0.02)O_(2)film achieves the highest electrical conductivity of 855 S cm-1with a carrier concentration of2.3×10^(20)cm^(-3)and high mobility of 23 cm^(2)V^(-1)s^(-1).The films exhibit a very high optical transparency of 89.5%in the visible light region.High-resolution X-ray photoemission spectroscopy and optical spectroscopy were combined to gain insights into the electronic structure of the Sn_(1-x)Ta_(x)O_(2)films.The optical bandgaps of the films are increased from 3.96 eV for the undoped SnO_(2)to 4.24 eV for the Sn_(0.98)Ta_(0.02)O_(2)film due to the occupation of the bottom of conduction band by free electrons,i.e.,the Burstein-Moss effect.Interestingly,a bandgap shrinkage is also directly observed due to the bandgap renormalization arising from many-body interactions.The double guarantee of transparency and conductivity in Sn_(1-x)Ta_(x)O_(2)films and the low-cost growth method provide a new platform for optoelectronic and solar cell applications.
基金Project supported by the German Research Foundation(Cluster of Excellence Center for Advancing Electronics Dresden(cfaed)partially performed within the Federal Cluster of Excellence EXC 1075 MERGE Technologies for Multifunctional Lightweight Structures
文摘The synthesis,structure and thermal behavior of [Y（dbm）3（H2 O）]（3）（dbm = 1,3-diphenyl-1,3-propandionate） and its use as a spin-coating precursor for Y2 O3 deposition is reported. Complex 3 was prepared by the reaction of [Y（NO3）3·6 H2 O]（1） with 3 equiv of Hdbm（2） in presence of NaOH. The molecular structure of 3 in the solid-state was determined by single X-ray crystal diffraction. Both C1 symmetric crystallographically independent species of 3 possess a YO7 coordination setup with minor deviation from an ideal capped octahedron coordination geometry（∧ enantiomer）. Complex 3 forms a1 D chain, due to intermolecular hydrogen bonds between the coordinated H2 O molecule and the 0 atom of the dbm ligand, respectively. The thermal decomposition behavior of 3 was investigated by thermogravimetric studies in the temperature range of 40-800 ℃ and 40-1300 ℃ under an oxygen and argon atmosphere, respectively. Powder X-ray diffraction（PXRD） measurements of the residues confirmed the formation of Y2 O3. Complex 3 was applied as a spin-coating precursor for yttrium oxide film formation on either Si wafers with a continuous 100 nm thick SiO2 film, or with a native oxide layer.The as-deposited Y2 O3 layers are smooth, conformal, dense and transparent and are of a thickness of 27 and 30 nm, respectively.
基金supported by the Fundamental Research Funds for the Central Universities(No.2021JCCXJD01)Key R&D and transformation projects in Qinghai Province(No.2021-HZ-808)Hebei Province(No.21314401D)。
文摘Lithium-rich manganese-based material shows great potential as the high specific cathode materials due to its low cost,environmental friendliness,high operating voltage and simple preparation process.However,the poor capacity retention and cycling performance caused by its unstable structure during cycling restrict the commercialization.In this work,Li_(1.2)Ni_(0.16)Mn_(0.56)Co_(0.08)O_(2)was synthesized utilizing a Coprecipitation method and different amount of La(PO_(3))_(3)(La(PO_(3))_(3)=2 wt%,4 wt%and 6 wt%)was selected as the coating layer to resolve the above issues.During the calcination process,La(PO_(3))_(3)reacts with impurities such as Li OH and Li_(2)CO_(3)on the lithium-rich surface to reduce the residual lithium on the surface,thus improving the interfacial stability,slowing down the corrosion of the electrolyte,and finally enhancing its electrochemical performance.The cathode materials coated with 4%of La(PO_(3))_(3)showed the best electrochemical performance in terms of capacity retention and cycling performance compared to the pristine NCM.The high initial discharge capacity of 214.21 m Ah/g and capacity retention of 94.2%after 100 cycles at 0.1 C can be obtained.This work provides an effective strategy to protect the cathode from corrosion and will promote its further practical applications in high specific Li-ion batteries.
