High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface...High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.展开更多
The carbonizing process and its influence on the thermionic electron emission properties of Mo-La_2O_3 cathode materials were investigated. The carbonized temperature, carbonized time and the pressure of C_6H_6 are ke...The carbonizing process and its influence on the thermionic electron emission properties of Mo-La_2O_3 cathode materials were investigated. The carbonized temperature, carbonized time and the pressure of C_6H_6 are key factors of the carbonizing process. The carbonized ratio of Mo-La_2O_3 cathode increases with the increase of carbonizing temperature at low temperature. The highest carbonized ratio is 19.7% obtained at 1723 K, then the carbonized ratio decreases rapidly if temperature increases further. The carbonized ratio increases with the prolongation of carbonizing time during the process of first 6 min., after that the carbonization ratio changes little with the time increase, and the carbonized ratio increases with the increase of the C_6H_6 pressure when the pressure is low, the maximum carbonized ratio reaches 19.7% at 1.5×10^(-2) Pa, then the carbonized ratio goes down sharply when the C_6H_6 pressure is over 1.5×10^(-2) Pa. The emission properties at different operated temperatures and the emission current stability of FU-6051 tubes (equipped) with Mo-La_2O_3 cathodes were also studied in the article. The study results indicate that the emission can keep stable only when the operating temperature is from 1700 to 1800 K and the carbonized layer must be composed by Mo_2C only. The FU-6051 tubes (equipped) with Mo-La_2O_3 cathodes have excellent stable emission current and the lifetime exceeds 3000 h when the cathode′s carbonized ratio is 19.7% operated at 1773 K.展开更多
P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2) was synthesized by a facile sol−gel method,and the effect of calcination temperature on the structure,morphology and electrochemical performance of samples was investigated.The re...P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2) was synthesized by a facile sol−gel method,and the effect of calcination temperature on the structure,morphology and electrochemical performance of samples was investigated.The results show that the sample obtained at 900℃ is pure P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2) phase with good crystallization,which consists of hexagon plate-shaped particles with the size and thickness of 2−4μm and 200−400 nm,respectively.The sample exhibits an initial specific discharge capacity of 243 mA·h/g at a current density of 26 mA/g with good cycling stability.The high specific capacity indicates that P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2) is a promising cathode material for sodiumion batteries.展开更多
Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs ...Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs is still plagued by the low specific capacity and poor rate capability.Herein,highly crystalline Mn2O3 materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs.The coordination degree between Mn2+and citric acid ligand plays a crucial role in the formation of the mesostructure,and the pore sizes can be easily tuned from 3.2 to 7.3 nm.Ascribed to the unique feature of nanoporous architectures,excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes.The Mn2O3 electrode exhibits high reversible capacity(233 mAh g−1 at 0.3 A g−1),superior rate capability(162 mAh g−1 retains at 3.08 A g−1)and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g−1.Moreover,the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods.These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.展开更多
LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) is extensively researched as one of the most widely used commercially materials for Li-ion batteries at present.However,the poor high-voltage performance(≥4.3 V)with low reversible cap...LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) is extensively researched as one of the most widely used commercially materials for Li-ion batteries at present.However,the poor high-voltage performance(≥4.3 V)with low reversible capacity limits its replacement for LiCoO_(2) in high-end digital field.Herein,three-in-one modification,Na-doping and Al_(2)O_(3)@Li_(3)BO_(3) dual-coating simultaneously,is explored for single-crystalline LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(N-NCM@AB),which exhibits excellent high-voltage performance.N-NCM@AB displays a discharge-specific capacity of 201.8 mAh g^(−1) at 0.2 C with a high upper voltage of 4.6 V and maintains 158.9 mAh g^(−1) discharge capacity at 1 C over 200 cycles with the corresponding capacity retention of 87.8%.Remarkably,the N-NCM@AB||graphite pouch-type full cell retains 81.2% of its initial capacity with high working voltage of 4.4 V over 1600 cycles.More importantly,the fundamental understandings of three-in-one modification on surface morphology,crystal structure,and phase transformation of N-NCM@AB are clearly revealed.The Na+doped into the Li–O slab can enhance the bond energy,stabilize the crystal structure,and facilitate Li+transport.Additionally,the interior surface layer of Li^(+)-ions conductor Li_(3)BO_(3) relieves the charge transfer resistance with surface coating,whereas the outer surface Al_(2)O_(3) coating layer is beneficial for reducing the active materials loss and alleviating the electrode/electrolyte parasite reaction.This three-in-one strategy provides a reference for the further research on the performance attenuation mechanism of NCM,paving a new avenue to boost the high-voltage performance of NCM cathode in Li-ion batteries.展开更多
锂硫电池因其高能量密度和低成本而成为最有发展前景的电化学储能器件之一。然而,多硫化物的“穿梭效应”、硫导电率低是锂硫电池商业化面临的主要挑战。本工作中,以Fe(NO)_(3)·9H_(2)O为铁源,NH4F为表面活性剂,通过简单的水热及...锂硫电池因其高能量密度和低成本而成为最有发展前景的电化学储能器件之一。然而,多硫化物的“穿梭效应”、硫导电率低是锂硫电池商业化面临的主要挑战。本工作中,以Fe(NO)_(3)·9H_(2)O为铁源,NH4F为表面活性剂,通过简单的水热及煅烧处理制备了Fe_(2)O_(3)纳米棒修饰炭布(CC)的柔性Fe_(2)O_(3)/CC复合材料。其中,Fe_(2)O_(3)中介孔的存在有利于电解质的渗透和充放电过程中锂离子的传输和扩散,同时其密集阵列暴露出的丰富活性位点可以实现多硫化物的高效吸附和快速转化,降低多硫化物的穿梭效应。电化学分析显示:Fe_(2)O_(3)/CC正极在0.1 C(1 C=1672 mA g^(−1))的电流密度下具有1250 mAh g^(-1)的高放电比容量,经100圈循环后比容量保持在789 mAh g^(-1)。在2 C的倍率下循环1000圈后仍能达到576 mAh g^(-1)的放电比容量,容量保持率为70%,明显优于对比样品。因此,Fe_(2)O_(3)/CC能够很好地抑制多硫化物的穿梭,提高电池倍率性能和循环稳定性。展开更多
For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular be...For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process.展开更多
锰基氧化物作为锌离子电池正极具有高比容量和低成本等优点,但在电化学循环过程中不可逆相变、锰的溶解和电极/电解质界面不稳定导致其在小电流密度、深度放电条件下的循环性能差.针对以上问题,合成了三维(3D)多孔MnOx立方盒子,并在其...锰基氧化物作为锌离子电池正极具有高比容量和低成本等优点,但在电化学循环过程中不可逆相变、锰的溶解和电极/电解质界面不稳定导致其在小电流密度、深度放电条件下的循环性能差.针对以上问题,合成了三维(3D)多孔MnOx立方盒子,并在其表面包覆In_(2)O_(3)层,获得3D多孔MnO_(x)@In_(2)O_(3)立方盒子.结果显示,MnO_(x)@In_(2)O_(3)立方盒子具有大量孔径约10 nm左右的孔,有利于H^(+)和Zn^(2+)的快速传输;In2O3包覆层均匀包覆于3D多孔MnO_(x)立方盒子的孔壁上,有利于抑制MnO_(x)在电化学循环过程中的不可逆相变和锰的溶解,稳定电极/电解质界面.电化学测试结果表明,该3D多孔MnO_(x)@In_(2)O_(3)电极在0.3 A/g的小电流密度、深度放电条件下能稳定循环400次以上,容量保持260 m A·h/g;在1.8 A/g电流密度下可稳定循环4000次以上,容量保持81m A·h/g;即使在高电流密度6.0 A/g下仍保持73.4 m A·h/g的高可逆容量.恒电流间隙滴定(GITT)和循环伏安测试结果表明,3D多孔MnO_(x)@In_(2)O_(3)电极比3D多孔MnO_(x)具有更高的离子扩散速率,有利于提升其高倍率容量.电化学阻抗谱结果表明,3D多孔MnO_(x)@In_(2)O_(3)电极具有比3D多孔MnO_(x)更稳定的电极/电解质界面,有利于提升其循环寿命.2000次循环后的扫描电子显微镜(SEM)结果表明,MnO_(x)@In_(2)O_(3)电极表面仍分布少量In_(2)O_(3),以确保电极/电解质界面和循环的稳定性.展开更多
本文采用高温光电子能谱方法对 L a2 O3- Mo阴极及碳化 L a2 O3- Mo阴极材料表面 L a2 O3 的化学稳定性进行了研究。实验结果表明 ,L a2 O3并不具备文献报道的极好的化学稳定性。材料中的 L a2 O3在高温、真空条件下 ,其部分晶格氧发生...本文采用高温光电子能谱方法对 L a2 O3- Mo阴极及碳化 L a2 O3- Mo阴极材料表面 L a2 O3 的化学稳定性进行了研究。实验结果表明 ,L a2 O3并不具备文献报道的极好的化学稳定性。材料中的 L a2 O3在高温、真空条件下 ,其部分晶格氧发生分离。 L a2 O3可以被 Mo2 C还原成单质 L a。单质 L a的结合能高于 L a2 O3的结合能。实验证实单质 L a3d5 / 2的结合能为 835 .96 e V,并首次给出 L a3d3/ 2的结合能实验数值为 85 2 .2 3e V。展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFB2503900)the National Natural Science Foundation of China(Grant No.52372203)+1 种基金the National Natural Science Foundation of China(Grant No.52202259)the Shandong Province Natural Science Foundation(ZR2022QE093).
文摘High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.
文摘The carbonizing process and its influence on the thermionic electron emission properties of Mo-La_2O_3 cathode materials were investigated. The carbonized temperature, carbonized time and the pressure of C_6H_6 are key factors of the carbonizing process. The carbonized ratio of Mo-La_2O_3 cathode increases with the increase of carbonizing temperature at low temperature. The highest carbonized ratio is 19.7% obtained at 1723 K, then the carbonized ratio decreases rapidly if temperature increases further. The carbonized ratio increases with the prolongation of carbonizing time during the process of first 6 min., after that the carbonization ratio changes little with the time increase, and the carbonized ratio increases with the increase of the C_6H_6 pressure when the pressure is low, the maximum carbonized ratio reaches 19.7% at 1.5×10^(-2) Pa, then the carbonized ratio goes down sharply when the C_6H_6 pressure is over 1.5×10^(-2) Pa. The emission properties at different operated temperatures and the emission current stability of FU-6051 tubes (equipped) with Mo-La_2O_3 cathodes were also studied in the article. The study results indicate that the emission can keep stable only when the operating temperature is from 1700 to 1800 K and the carbonized layer must be composed by Mo_2C only. The FU-6051 tubes (equipped) with Mo-La_2O_3 cathodes have excellent stable emission current and the lifetime exceeds 3000 h when the cathode′s carbonized ratio is 19.7% operated at 1773 K.
基金the financial supports from the Natural Science Foundation of Hunan Province,China(No.2020JJ5102)the Scientific Research Fund of Hunan Provincial Education Department,China(No.19A111).
文摘P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2) was synthesized by a facile sol−gel method,and the effect of calcination temperature on the structure,morphology and electrochemical performance of samples was investigated.The results show that the sample obtained at 900℃ is pure P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2) phase with good crystallization,which consists of hexagon plate-shaped particles with the size and thickness of 2−4μm and 200−400 nm,respectively.The sample exhibits an initial specific discharge capacity of 243 mA·h/g at a current density of 26 mA/g with good cycling stability.The high specific capacity indicates that P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2) is a promising cathode material for sodiumion batteries.
基金the Young Thousand Talented Program and the National Natural Science Foundation of China (21671073 and 21621001)the “111” Project of the Ministry of Education of China (B17020)Program for JLU Science and Technology Innovative Research Team
文摘Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs is still plagued by the low specific capacity and poor rate capability.Herein,highly crystalline Mn2O3 materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs.The coordination degree between Mn2+and citric acid ligand plays a crucial role in the formation of the mesostructure,and the pore sizes can be easily tuned from 3.2 to 7.3 nm.Ascribed to the unique feature of nanoporous architectures,excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes.The Mn2O3 electrode exhibits high reversible capacity(233 mAh g−1 at 0.3 A g−1),superior rate capability(162 mAh g−1 retains at 3.08 A g−1)and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g−1.Moreover,the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods.These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(52070194,51902347,51908555,and 51822812)Natural Science Foundation of Hunan Province(2020JJ5741)the Graduate Innovation Project of Central South University(2020zzts093).
文摘LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) is extensively researched as one of the most widely used commercially materials for Li-ion batteries at present.However,the poor high-voltage performance(≥4.3 V)with low reversible capacity limits its replacement for LiCoO_(2) in high-end digital field.Herein,three-in-one modification,Na-doping and Al_(2)O_(3)@Li_(3)BO_(3) dual-coating simultaneously,is explored for single-crystalline LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(N-NCM@AB),which exhibits excellent high-voltage performance.N-NCM@AB displays a discharge-specific capacity of 201.8 mAh g^(−1) at 0.2 C with a high upper voltage of 4.6 V and maintains 158.9 mAh g^(−1) discharge capacity at 1 C over 200 cycles with the corresponding capacity retention of 87.8%.Remarkably,the N-NCM@AB||graphite pouch-type full cell retains 81.2% of its initial capacity with high working voltage of 4.4 V over 1600 cycles.More importantly,the fundamental understandings of three-in-one modification on surface morphology,crystal structure,and phase transformation of N-NCM@AB are clearly revealed.The Na+doped into the Li–O slab can enhance the bond energy,stabilize the crystal structure,and facilitate Li+transport.Additionally,the interior surface layer of Li^(+)-ions conductor Li_(3)BO_(3) relieves the charge transfer resistance with surface coating,whereas the outer surface Al_(2)O_(3) coating layer is beneficial for reducing the active materials loss and alleviating the electrode/electrolyte parasite reaction.This three-in-one strategy provides a reference for the further research on the performance attenuation mechanism of NCM,paving a new avenue to boost the high-voltage performance of NCM cathode in Li-ion batteries.
文摘锂硫电池因其高能量密度和低成本而成为最有发展前景的电化学储能器件之一。然而,多硫化物的“穿梭效应”、硫导电率低是锂硫电池商业化面临的主要挑战。本工作中,以Fe(NO)_(3)·9H_(2)O为铁源,NH4F为表面活性剂,通过简单的水热及煅烧处理制备了Fe_(2)O_(3)纳米棒修饰炭布(CC)的柔性Fe_(2)O_(3)/CC复合材料。其中,Fe_(2)O_(3)中介孔的存在有利于电解质的渗透和充放电过程中锂离子的传输和扩散,同时其密集阵列暴露出的丰富活性位点可以实现多硫化物的高效吸附和快速转化,降低多硫化物的穿梭效应。电化学分析显示:Fe_(2)O_(3)/CC正极在0.1 C(1 C=1672 mA g^(−1))的电流密度下具有1250 mAh g^(-1)的高放电比容量,经100圈循环后比容量保持在789 mAh g^(-1)。在2 C的倍率下循环1000圈后仍能达到576 mAh g^(-1)的放电比容量,容量保持率为70%,明显优于对比样品。因此,Fe_(2)O_(3)/CC能够很好地抑制多硫化物的穿梭,提高电池倍率性能和循环稳定性。
基金Project supported by the Enterprise Science and Technology Correspondent for Guangdong Province,China (Grant No.GDKTP2021015200)。
文摘For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process.
文摘锰基氧化物作为锌离子电池正极具有高比容量和低成本等优点,但在电化学循环过程中不可逆相变、锰的溶解和电极/电解质界面不稳定导致其在小电流密度、深度放电条件下的循环性能差.针对以上问题,合成了三维(3D)多孔MnOx立方盒子,并在其表面包覆In_(2)O_(3)层,获得3D多孔MnO_(x)@In_(2)O_(3)立方盒子.结果显示,MnO_(x)@In_(2)O_(3)立方盒子具有大量孔径约10 nm左右的孔,有利于H^(+)和Zn^(2+)的快速传输;In2O3包覆层均匀包覆于3D多孔MnO_(x)立方盒子的孔壁上,有利于抑制MnO_(x)在电化学循环过程中的不可逆相变和锰的溶解,稳定电极/电解质界面.电化学测试结果表明,该3D多孔MnO_(x)@In_(2)O_(3)电极在0.3 A/g的小电流密度、深度放电条件下能稳定循环400次以上,容量保持260 m A·h/g;在1.8 A/g电流密度下可稳定循环4000次以上,容量保持81m A·h/g;即使在高电流密度6.0 A/g下仍保持73.4 m A·h/g的高可逆容量.恒电流间隙滴定(GITT)和循环伏安测试结果表明,3D多孔MnO_(x)@In_(2)O_(3)电极比3D多孔MnO_(x)具有更高的离子扩散速率,有利于提升其高倍率容量.电化学阻抗谱结果表明,3D多孔MnO_(x)@In_(2)O_(3)电极具有比3D多孔MnO_(x)更稳定的电极/电解质界面,有利于提升其循环寿命.2000次循环后的扫描电子显微镜(SEM)结果表明,MnO_(x)@In_(2)O_(3)电极表面仍分布少量In_(2)O_(3),以确保电极/电解质界面和循环的稳定性.
文摘本文采用高温光电子能谱方法对 L a2 O3- Mo阴极及碳化 L a2 O3- Mo阴极材料表面 L a2 O3 的化学稳定性进行了研究。实验结果表明 ,L a2 O3并不具备文献报道的极好的化学稳定性。材料中的 L a2 O3在高温、真空条件下 ,其部分晶格氧发生分离。 L a2 O3可以被 Mo2 C还原成单质 L a。单质 L a的结合能高于 L a2 O3的结合能。实验证实单质 L a3d5 / 2的结合能为 835 .96 e V,并首次给出 L a3d3/ 2的结合能实验数值为 85 2 .2 3e V。
