Ni doped La_(0.6)Sr_(0.4)FeO_(3-δ) symmetrical electrode for solid oxide fuel cells

The conventional Ni cermet anode suffers from severe carbon deposition and sulfur poisoning when fossil fuels are used. Alternative anode materials are desired for high performance hydrocarbon fuel solid oxide fuel cells （SOFCs）. We report the rational design of a very active Ni doped La0.6Sr0.4FeO3‐δ（LSFN） electrode for hydrocarbon fuel SOFCs. Homogeneously dispersed Ni‐Fe alloy nanoparticles were in situ extruded onto the surface of the LSFN particles during the operation of the cell. Sym‐metric SOFC single cells were prepared by impregnating a LSFN precursor solution onto a YSZ （yt‐tria stabilized zirconia） monolithic cell with a subsequent heat treatment. The open circuit voltage of the LSFN symmetric cell reached 1.18 and 1.0 V in humidified C3H8 and CH4 at 750？？, respective‐ly. The peak power densities of the cells were 400 and 230 mW/cm2 in humidified C3H8 and CH4, respectively. The electrode showed good stability in long term testing, which revealed LSFN has good catalytic activity for hydrocarbon fuel oxidation.

Hydrogen production from methane and carbon dioxide mixture using all-solid-state electrochemical cell based on a proton-conducting membrane and redox-robust composite electrodes

In recent years, interest in hydrogen as a fuel has sharply increased in the field of alternative and green energy due to its high energy capability and zero-emission behaviour. As a result, research in the development of new highly efficient methods for producing high-purity hydrogen is relevant. This paper presents, for the first time, the test results of an electrochemical cell with a proton-conducting La_(0.9)Sr_(0.1)ScO_(3-δ) electrolyte and symmetrical Sr_(1.95)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)+ La_(0.9)Sr_(0.1)Sc_(0.9)Co_(0.1)O_(3-δ) electrodes as a hybrid setup for electricity generation in proton ceramic fuel cell mode, for hydrogen separation from H_(2)+ Ar mixture and the production of high-purity hydrogen from methane with simultaneous CO_(2) utilization.It was found that this electrochemical cell generates high flow rates of hydrogen during its separation through a proton-conducting membrane from H_(2)+ Ar mixture, about 500 cm^(3)h^(-1)cm^(-2)at a current density of 0.6 A cm^(-2)as well as about 370 cm^(3) h^(-1)cm^(-2)at a current density of 0.5 A cm^(-2) from CH_(4)+ CO_(2) mixture at 800 ℃ which shows that these cells are promising for hydrogen production.

Cerium and ruthenium co-doped La_(0.7)Sr_(0.3)FeO_(3-δ) as a high-efficiency electrode for symmetrical solid oxide fuel cell

Symmetrical solid oxide fuel cells(SSOFCs)could be alternative energy conversion devices due to their simple fabrication process and low cost.Herein,perovskite La_(0.6)Ce_(0.1)Sr_(0.3)Fe_(0.95)Ru_(0.05O3-δ)(LCSFR)was synthesized and evaluated as a high-performance electrode for SSOFCs based on the electrolyte of La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-δ)(LSGM).LCSFR retains their stable perovskite crystal structure in both reducing and oxidizing atmospheres,though a minor amount of LaSrFeO4 phase is present under reducing conditions.Morphology investigation shows that homogeneously dispersed Ru metallic nanoparticles are exsolved on the surface of LCSFR after being reduced.The polarization resistance(Rp)of LCSFR-CGO(Ce_(0.9)Gd_(0.1O2-δ))is about 0.11Ω·cm^(2)at 800℃in air,while the value of Rp for LCSFR-CGO in wet H_(2)(3%H_(2)O)increases up to 0.32Ω·cm^(2).The symmetrical LCSFR-CGOILSGMILCSFR-CGO cell demonstrates a performance with an open circuit potential(OCV)of 1.07 V and a maximum peak power density of 904 mW/cm^(2)at 800℃using wet H2 as the fuel.This high performance indicates that LCSFR is a candidate electrode for SSOFCs.

Cobalt and Titanium substituted SrFeO_(3) based perovskite as efficient symmetrical electrode for solid oxide fuel cell

One of the key tasks in solid oxide fuel cell research is to develop cost-competitive electrodes that work efficiently in wide range of air and fuel utilizations.Herein,we promote our study to a series of Cobalt and Titanium substituted La_(0.4)Sr_(0.6)Fe_(0.7)Ti_(0.3-x)Co_(x)O_(3-δ)(LSFTC,x=0,0.05,0.1,0.2)perovskite oxides.It is shown that Cobalt doping effectively improves the electrical conductivity and oxygen electrochemical reduction activity,yielding decreased cathode polarization resistance and lower dependence of pO_(2) change.For example,σ_(600℃)=81 S/cm and R_(p,C750℃)=0.1 Ω cm^(2) for LSFTC-5 are obtained in pO_(2)=0.21 atm.In anode conditions of wet H2,the LSFTC cubic perovskites are partially reduced to hybrid structure of ABO_(3)-A_(2)BO_(4)-metal with Cobalt doping amount less than 10% and are fully decomposed to A_(2)BO_(4)-metal with 20% doping.The higher Cobalt substitution generates more nano particles exsolution,which promotes anode processes at low temperatures.However,the generated AO-rich compositions are shown detrimental to anode performance in both conducting property and anode catalytic activity under low H_(2) partial pressures.In current study,the electrodes are evaluated under practical working conditions with broad pO_(2) and pH_(2),which provides guidelines for industrial-applicable SrFeO_(3) based symmetrical electrode development.

Ultralong Life Symmetric Potassium Ion Batteries Using a Bipolar Cr/Ti Based Layered Material

Based on low cost and earth abundance potassium resources,potassium-ion batteries have been regarded as the potential candidate for large-scale energy storage applications for renewable energy and smart grid.Although some earlier works have proposed reversible insertion/extraction of K^(+)ions in K cells,their cycle instability is insufficient for the further application of potassium-ion batteries.Herein,we report a symmetric potassium-ion battery with ultralong life employing a bipolar Cr/Ti based layered oxide,which contains two electrochemically active transition metals with the redox couples of Cr^(4+)/Cr^(3+)and Ti^(4+)/Ti^(3+)working on the cathode and anode side,respectively.Moreover,the(de)intercalation process in the structure and the in-situ electrochemical exchange process are investigated by ex-situ XRD.As a result,the symmetric cell based on the obtained K-based bipolar layered material exhibits a reversible capacity of 102 mA·h/g between 0.5 V and 3.5 V at 20 mA/g,an ultralong cycle life of 2000 cycles with a capacity retention of 80%and high rate capabilities.The outstanding cycling stability and rate performance endow this work with promising advantages for the future development of the novel energy storage system.