定氧电池氧化锆电解质中的氧位分布与参比电极的选择

用稳态法求得氧化锆固体电解质内的氧位分布，从理论上阐明了钢液定氧电池参比电极的选择原则。在１６００℃下，钢液含氧量小于３００×１０^（－６）时，Ｃｒ／Ｃｒ_２Ｏ_３参比电极优于Ｍｏ／ＭｏＯ_２参比电极；而钢液含氧量大于３００×１０^（－６）时，使用Ｍｏ／ＭｏＯ_２，参比电极比Ｃｒ／Ｃｒ_２Ｏ_３参比电极的误差更小。氧含量极低时，不宜采用Ｍｏ／ＭｏＯ_２作参比电极。

钢水定氧半电池电极粉的预处理工艺研究

炼钢过程中钢水氧含量的准确测量关键在于定氧半电池,其参比电极粉以Cr2O3和Cr粉末为主要原料。研究Cr2O3和Cr粉末的混合比例,并进行相应的装配前预处理,以制备适用于低氧端测试的半电池参比电极粉。结果表明,为保证参比气氛氧分压的稳定,参比电极粉中Cr必须过量;采用球磨混合方式,通过预烧结处理的参比电极粉,可有效防止高温烧结团聚现象,提高定氧电信号的测量速度和准确性。

H_2O/CO_2 co-electrolysis in solid oxide electrolysis cells

A solid oxide electrolysis cell(SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational principle of an SOEC for co-electrolyzing H2O and CO2to generate syngas was reviewed. The recent development of high temperature H2O/CO2co-electrolysis from solid oxide single electrolysis cell was introduced. Also investigated was H2O/CO2co-electrolysis research using hydrogen electrode-supported nickel(Ni)-yttria-stabilized zirconia(YSZ)/YSZ/Sr-doped LaMnO3(LSM)-YSZ cells in our group. With 50 % H2O,15.6 % H2and 34.4 % CO2inlet gas to Ni- YSZ electrode,polarization curves(I- U curves) and electrochemical impedance spectra(EIS) were measured at 800 ℃ and 900 ℃. Long-term durability of electrolysis was carried out with the same inlet gas at 900 ℃ and 0.2 A/cm2. In addition,the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.

Theoretical Aspects on Doped-Zirconia for Solid Oxide Fuel Cells:from Structure to Conductivity

Solid oxide fuel cells(SOFCs)are regarded to be a key clean energy system to convert chemical energy(e.g.H_(2) and O_(2))into electrical energy with high efficiency,low carbon footprint,and fuel flexibility.The electrolyte,typically doped zirconia,is the"state of the heart"of the fuel cell technologies,determining the performance and the operating temperature of the overall cells.Yttria stabilized zirconia(YSZ)have been widely used in SOFC due to its excellent oxide ion conductivity at high temperature.The composition and temperature dependence of the conductivity has been hotly studied in experiment and,more recently,by theoretical simulations.The characterization of the atomic structure for the mixed oxide system with different compositions is the key for elucidating the conductivity behavior,which,however,is of great challenge to both experiment and theory.This review presents recent theoretical progress on the structure and conductivity of YSZ electrolyte.We compare different theoretical methods and their results,outlining the merits and deficiencies of the methods.We highlight the recent results achieved by using stochastic surface walking global optimization with global neural network potential(SSW-NN)method,which appear to agree with available experimental data.The advent of machine-learning atomic simulation provides an affordable,efficient and accurate way to understand the complex material phenomena as encountered in solid electrolyte.The future research directions for design better electrolytes are also discussed.

Fuel Cell Technology for Propulsion and Power Generation of Ships： Feasibility Study on Ocean Research Vessel Sagarnidhi

Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging technology with negligible pollution. More significantly for a research ship, emission levels need to be substantially low to have quality measurements. A feasibility study is carried-out First time in the world, to drive an ice class multi-disciplinary ORV （Oceanography Research Vessel） Sagarnidbi, using hydrogen powered fuel cell. Sagamidhi is equipped with special equipments viz., Deep Sea winch, specially designed cranes for Launching and retrieval of ROV （Remotely Operable Vehicle）, DSMC （Deep Sea Mining Crawler）, Tsunami systems, manned/unmanned submersible and ACS （Autonomous Coring System） and other facilities that support research in Indian, International and Antarctic waters. Beside this, the propulsion system along with DP （Dynamic Positioning）, centralized air conditioning and special equipments require enormous electrical power. The combustion of diesel oil in an engine, that coupled with an alternator generates electrical power required, along with NOx （Nitrous Oxides）, SOx （Sulphur Oxides） and PM （Particulate Matter） emissions. Shipping industry is the fourth largest contributor to air pollution and carbon emissions, particularly in coastal areas, and the growth rate makes the problem even more critical. Stringent international air pollution regulation and increasing fuel price paves the way for an alternative ＂green emission technology＂. Various fuel cells were analyzed with different combination of fuel, electrolyte and electrodes. From the analysis, it has been found that SOFC （Solid Oxide Fuel Cell） is most suitable for the present scenario. A fuel cell designed with hydrogen as fuel, zirconium oxides stabilized with yttrium oxide as electrolyte and zirconium electrodes is used for 1.5 MW power output and 0.5 MW through regenerator. Volume required for storage of hydrogen is in line with volume of fuel and a high standard safety measures were taken using sensors. The present system saves 3000 MT/annum of diesel oil costing 3,000,000 USD approximately.

Operational Robustness Studies of Solid Oxide Electrolysis Stacks

Stacks of solid oxide cells which can be run as both electrolysers and fuel cells have been tested for robustness towards simulations of stress conditions which are likely to occur during operation of solid oxide electrolysis systems, for which the energy supply comes from renewable sources, such as wind mills and solar cells. Such conditions are thermo mechanical stress conditions as well as loss of fuel and air supply. The cells have Ni/YSZ （yttria stabilized zirconia） fuel electrodes, YSZ electrolytes, and LSCF （lanthanum strontium cobalt ferrite） oxygen electrodes with a CGO （cerium gadolinium oxide） barrier layer. In the stacks, the cells are separated by chromium rich steel interconnects. The robustness tests of stacks are one step in the development of a SOEC （solid oxide electrolysis cell） core; the core component in a SOEC system, including one or more SOEC stacks, heaters, heat exchangers, insulation, and feed troughs.

SnO2-reduced graphene oxide nanoribbons as anodes for lithium ion batteries with enhanced cycling stability

A nanocomposite material of SnO2-reduced graphene oxide nanoribbons has been developed. In this composite, the reduced graphene oxide nanoribbons are uniformly coated by nanosized SnO2 that formed a thin layer of SnO2 on the surface. When used as anodes in lithium ion batteries, the composite shows outstanding electrochemical performance with the high reversible discharge capacity of 1,027 mAh/g at 0.1 A/g after 165 cycles and 640 mAh/g at 3.0 A/g after 160 cycles with current rates varying from 0.1 to 3.0 A/g and no capacity decay after 600 cycles compared to the second cycle at a current density of 1.0 A/g. The high reversible capacity, good rate performance and excellent cycling stability of the composite are due to the synergistic combination of electrically conductive reduced graphene oxide nanoribbons and SnO2, The method developed here is practical for the large-scale development of anode materials for lithium ion batteries.

Ab initio prediction of borophene as an extraordinary anode material exhibiting ultrafast directional sodium diffusion for sodium-based batteries

Density functional theory calculations and ab initio molecular dynamics simulations are performed to study the feasibility of using borophene, a newly synthesized two-dimensional sheet of boron, as an anode material for sodium-ion and sodium-oxygen batteries. The theo- retical capacity of borophene is found to be as high as 1,218 mAh g-1 （Nao.sB）. More importantly, it is demonstrated that the sodium diffusion energy barrier along the valley direction is as low as 0.0019 eV, which corresponds to a diffusivity of more than a thousand times higher than that of conventional anode materials such as Na2Ti307 and Na3Sb. Hence, the use of borophene will revolutionize the rate capability of sodium-based batteries. Moreover, it is predicted that, during the sodiation process, the average open-circuit voltage is 0.53 V, which can effectively sup- press the formation of dendrites while maximizing the energy density. The metallic feature and structural integrity of borophene can be well preserved at different sodium concentrations, demonstrating good electronic conductivity and stable cyclability.

Superior cycling stability of H_(0.642)V_(2)O_(5)·0.143H_(2)O in rechargeable aqueous zinc batteries

To increase the service life of rechargeable batteries,transition metal oxide hosts with high structural stability for the intercalation of carrier ions are important.Herein,we reconstruct the crystal structure of a commercial V_(2)O_(5)by pre-intercalating H^(+)and H_(2)O pillars using a facile hydrothermal reaction and obtain a bi-layer structured H_(0.642)V_(2)O_(5)·0.143H_(2)O(HVO)as an excellent host for aqueous Zn-ion batteries.Benefiting from the structural reconstruction,the irreversible“layer-to-amorphous”phase evolution during cycling is considerably less,resulting in ultra-high cycling stability of HVO with nearly no capacity fading even after 500 cycles at a current density of 0.5Ag^(-1).Moreover,a synthetic proton and Zn^(2+)intercalation mechanism in the HVO host is demonstrated.This work provides both a facile synthesis method for the preparation of V-based compounds and a new viewpoint for achieving high-performance host materials.