使用喷雾干燥法制备了Li1+2xMn0.3+xNi0.3-3xCr0.4O2(x=1/60、1/30、1/20、1/15、1/12)系列样品,并借助XRD,SEM,ICP,XPS,IR和Raman等手段对所制备系列样品的结构、价态及电化学性能进行了表征。研究表明,Li1+2xMn0.3+xNi0.3-3xCr0.4O2...使用喷雾干燥法制备了Li1+2xMn0.3+xNi0.3-3xCr0.4O2(x=1/60、1/30、1/20、1/15、1/12)系列样品,并借助XRD,SEM,ICP,XPS,IR和Raman等手段对所制备系列样品的结构、价态及电化学性能进行了表征。研究表明,Li1+2xMn0.3+xNi0.3-3xCr0.4O2系列样品均具有典型的富锂层状固溶体型的晶体结构特征,且在其XRD图谱中未观测到任何杂相的存在。然而,XPS的数据表明Cr3+与Cr6+共存于各个样品中,且由于Cr6+的存在使得样品表现出强烈的吸湿性。Cr6+可通过水洗处理去除。对于它们的电化学特征而言,未经水洗处理的样品由于具有强烈的吸湿性,其电化学性能很差。水洗处理后的系列样品表现出典型的三元富锂层状固溶体的电化学行为,其首次放电比容量随着样品中Li和Mn含量的增加而增大。样品Li1.17Mn0.38Ni0.05Cr0.4O2的首次放电比容量为203 mA h/g,50次循环后容量保持率为71%。展开更多
The NbO electrode materials were successfully synthesized by high-temperature solid-phase method using Nb powders and Nb2O5 powders as raw materials. The crystalline structure, morphology, and electrochemical properti...The NbO electrode materials were successfully synthesized by high-temperature solid-phase method using Nb powders and Nb2O5 powders as raw materials. The crystalline structure, morphology, and electrochemical properties of the obtained materials were characterized by X-ray diffi＇action （XRD）, scanning electron microscopy （SEM）, dynamic light scattering instrument （DLSA）, half- cell charge-discharge tests, and cyclic voltammetry （CV）. The reaction mechanism of lithium with NbO was inves- tigated by ex-situ XRD studies. The results show that material average Li storage voltage is nearly located at 1.6 V, and the lithium intercalation into NbO remains a single-phase process. For the first discharge, a capacity of 355 mAh·g^-1 is obtained at a current rate of 0.1C, and 293 mAh·g^-1is maintained after 50 cycles, whereas a capacity of 416 mAh·g^-1 is obtained at a current rate of 0.1C alter ball milling. And 380 mAh·g^-1 reversible capacity remains for the ball milling sample.展开更多
The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied, and a basis for the materials selection of sour gas well bushing was provided in H2S, CO2 and saline coex...The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied, and a basis for the materials selection of sour gas well bushing was provided in H2S, CO2 and saline coexisting environment. Under acidic condiction, hydrogen atoms greatly entered into the material and caused the material properties changed. Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment. PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated, hydrogen charging after reacting in autoclave. The corrosion product film was observed through SEM. The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time. Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film. A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix, but cracked holes which will accelerate partial corrosion of the sample were also observed.展开更多
The present work focuses on the structural stability upon hydrogenation of three typical La-Mg-Ni-based alloys： La2 MgNi9, LaaMgNi14 and La4MgNi19. Structural changes during gaseous and electrochemical cycles were ch...The present work focuses on the structural stability upon hydrogenation of three typical La-Mg-Ni-based alloys： La2 MgNi9, LaaMgNi14 and La4MgNi19. Structural changes during gaseous and electrochemical cycles were characterized, and the influence of the structure distortion on the hydrogen storage properties was concerned. Hydrogen-induced amor- phization （HIA） and disproportionation of the three alloys have occurred during both the gaseous and electrochemical cycles. Structural stability of the phase structures in the La-Mg-Ni system is found to follow the order： LaNi5- 〉 （La,Mg）5Ni19 〉 （La,Mg）2Ni7 〉 （La,Mg）Ni3 〉 （La,Mg）Ni2. HIA increases thermal stability of the metal hydrides and difficulty to dehydrogenation and leads to degradation of both the gaseous and electrochemical capacities. Interestingly, LaEMgNi9 with poor stability presents elevated discharge capability even at 60 ℃ which can be attributed to increase in the hydrogen desorption capability and inhibition of the self-discharge induced by severe HIA at higher temperatures. In addition, HIA in the electrochemical reactions is obviously weaker than the extent during the gaseous cycles, which is mainly due to the slower hydrogenation speed. The development of HIA in the gaseous and electrochemical process is considered to follow the direct and gradual modes, respectively.展开更多
A Co-Mg co-substituted LiNi0.87Co0.10Mg0.03O2 cathode material was prepared by a co-precipitation method. The prepared LiNi0.87Co0.10Mg0.03O2 exhibits excellent electrochemical properties, such as initial discharge ca...A Co-Mg co-substituted LiNi0.87Co0.10Mg0.03O2 cathode material was prepared by a co-precipitation method. The prepared LiNi0.87Co0.10Mg0.03O2 exhibits excellent electrochemical properties, such as initial discharge capacities of 202.6 mA.h/g and 190.5 mA.h/g at 0.2C and 1C rate, respectively, in operating voltage range of 3.0-4.3 V （versus Li^＋/Li）. The capacity retentions are 96.1% and 93.4% at 0.2C and 1C, respectively, after 50 cycles. Moreover, the cycle performance of the sample was investigated in a 053048-type square Li ion battery. This type of battery can keep 81.7% of initial capacity after 500 charge-discharge cycles at 1C rate, which is close to that of commercial LiCoO2 battery. Therefore, the as-prepared material is capable of such high energy applications as portable product power.展开更多
文摘以单分散法制备的聚甲基丙烯酸甲酯(PMMA)微球为模板,合成三维多孔(3DOM)LiMnPO_4锂电池正极材料,制备的材料为橄榄石型结构。N_2吸附-脱附分析显示,3DOM LiMnPO_4比表面积较大,为34.63 m^2/g。电化学性能测试表明,首次比容量接近于120 m A·h/g,循环充放电60次时仍保持较好的稳定性。模板法获得的LiMnPO_4呈多孔结构,有利于降低离子或电荷迁移到电解液或电极表面的阻力,从而降低了电极表面的极化,有利于锂离子脱嵌,进而提高充放电的循环稳定性。
文摘使用喷雾干燥法制备了Li1+2xMn0.3+xNi0.3-3xCr0.4O2(x=1/60、1/30、1/20、1/15、1/12)系列样品,并借助XRD,SEM,ICP,XPS,IR和Raman等手段对所制备系列样品的结构、价态及电化学性能进行了表征。研究表明,Li1+2xMn0.3+xNi0.3-3xCr0.4O2系列样品均具有典型的富锂层状固溶体型的晶体结构特征,且在其XRD图谱中未观测到任何杂相的存在。然而,XPS的数据表明Cr3+与Cr6+共存于各个样品中,且由于Cr6+的存在使得样品表现出强烈的吸湿性。Cr6+可通过水洗处理去除。对于它们的电化学特征而言,未经水洗处理的样品由于具有强烈的吸湿性,其电化学性能很差。水洗处理后的系列样品表现出典型的三元富锂层状固溶体的电化学行为,其首次放电比容量随着样品中Li和Mn含量的增加而增大。样品Li1.17Mn0.38Ni0.05Cr0.4O2的首次放电比容量为203 mA h/g,50次循环后容量保持率为71%。
基金financially supported by the National Science and Technology Support Project of China(No.2007BAE12B01)the Science and Technology Project of Changsha(No.k1201039-11)
文摘The NbO electrode materials were successfully synthesized by high-temperature solid-phase method using Nb powders and Nb2O5 powders as raw materials. The crystalline structure, morphology, and electrochemical properties of the obtained materials were characterized by X-ray diffi＇action （XRD）, scanning electron microscopy （SEM）, dynamic light scattering instrument （DLSA）, half- cell charge-discharge tests, and cyclic voltammetry （CV）. The reaction mechanism of lithium with NbO was inves- tigated by ex-situ XRD studies. The results show that material average Li storage voltage is nearly located at 1.6 V, and the lithium intercalation into NbO remains a single-phase process. For the first discharge, a capacity of 355 mAh·g^-1 is obtained at a current rate of 0.1C, and 293 mAh·g^-1is maintained after 50 cycles, whereas a capacity of 416 mAh·g^-1 is obtained at a current rate of 0.1C alter ball milling. And 380 mAh·g^-1 reversible capacity remains for the ball milling sample.
基金Funded by the National Natural Science Foundation of China(No. 50904050)the Basic Projects of Sichuan Province(2011JY0106)the Postdoctoral Science Foundation(20110490810)
文摘The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied, and a basis for the materials selection of sour gas well bushing was provided in H2S, CO2 and saline coexisting environment. Under acidic condiction, hydrogen atoms greatly entered into the material and caused the material properties changed. Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment. PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated, hydrogen charging after reacting in autoclave. The corrosion product film was observed through SEM. The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time. Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film. A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix, but cracked holes which will accelerate partial corrosion of the sample were also observed.
基金supported financially by the National Natural Science Foundation of China (No.51761032)the University Foundation of Inner Mongolia (No.NJZZ18142)
文摘The present work focuses on the structural stability upon hydrogenation of three typical La-Mg-Ni-based alloys： La2 MgNi9, LaaMgNi14 and La4MgNi19. Structural changes during gaseous and electrochemical cycles were characterized, and the influence of the structure distortion on the hydrogen storage properties was concerned. Hydrogen-induced amor- phization （HIA） and disproportionation of the three alloys have occurred during both the gaseous and electrochemical cycles. Structural stability of the phase structures in the La-Mg-Ni system is found to follow the order： LaNi5- 〉 （La,Mg）5Ni19 〉 （La,Mg）2Ni7 〉 （La,Mg）Ni3 〉 （La,Mg）Ni2. HIA increases thermal stability of the metal hydrides and difficulty to dehydrogenation and leads to degradation of both the gaseous and electrochemical capacities. Interestingly, LaEMgNi9 with poor stability presents elevated discharge capability even at 60 ℃ which can be attributed to increase in the hydrogen desorption capability and inhibition of the self-discharge induced by severe HIA at higher temperatures. In addition, HIA in the electrochemical reactions is obviously weaker than the extent during the gaseous cycles, which is mainly due to the slower hydrogenation speed. The development of HIA in the gaseous and electrochemical process is considered to follow the direct and gradual modes, respectively.
基金Project(2010DFA72760)supported by US.China Collaboration on Cutting-edge Technology Development of Electric VehiclesProjects(50901009,51271029)supported by the National Natural Science Foundation of ChinaProject(12QNJJ013)supported by the Fundamental Research Funds for the Central Universities,China
文摘A Co-Mg co-substituted LiNi0.87Co0.10Mg0.03O2 cathode material was prepared by a co-precipitation method. The prepared LiNi0.87Co0.10Mg0.03O2 exhibits excellent electrochemical properties, such as initial discharge capacities of 202.6 mA.h/g and 190.5 mA.h/g at 0.2C and 1C rate, respectively, in operating voltage range of 3.0-4.3 V （versus Li^＋/Li）. The capacity retentions are 96.1% and 93.4% at 0.2C and 1C, respectively, after 50 cycles. Moreover, the cycle performance of the sample was investigated in a 053048-type square Li ion battery. This type of battery can keep 81.7% of initial capacity after 500 charge-discharge cycles at 1C rate, which is close to that of commercial LiCoO2 battery. Therefore, the as-prepared material is capable of such high energy applications as portable product power.
