A robust fluorine-containing ceramic cathode for direct CO_(2) electrolysis in solid oxide electrolysis cells

Stro ntium-doped lanthanum ferrite(LSF)is a potential ceramic cathode for direct CO_(2) electrolysis in solid oxide electrolysis cells(SOECs),but its application is limited by insufficient catalytic activity and stability in CO_(2)-containing atmospheres.Herein,a novel strategy is proposed to enhance the electrolytic performance as well as chemical stability,achieved by doping F into the O-site of the perovskite LSF.Doping F does not change the phase structure but reduces the cell volume and improves the chemical stability in a CO_(2)-rich atmosphere.Importantly,F doping favors oxygen vacancy formation,increases oxygen vacancy concentration,and enhances the CO_(2) adsorption capability.Meanwhile,doping with F greatly improves the kinetics of the CO_(2) reduction reaction.For example,kchem increases by 78%from3.49×10^(-4) cm s^(-1) to 6.24×10^(-4) cm s^(-1),and Dchem doubles from 4.68×10^(-5) cm^(2) s^(-1) to 9.45×10^(-5)cm^(2) s^(-1).Consequently,doping F significantly increases the electrochemical performance,such as reducing R_(p) by 52.2%from 0.226Ωcm^(2) to 0.108Ωcm^(2) at 800℃.As a result,the single cell with the Fcontaining cathode exhibits an extremely high current density of 2.58 A cm^(-2) at 800℃and 1.5 V,as well as excellent durability over 200 h for direct CO_(2) electrolysis in SOECs.

Multi-Dimensional Models of SiC Power MOSFET for Accurately Predicting the Characteristics

The paper presents a compact simulation program with integrated circuit emphasis(SPICE)model for a 1200V/19A Silicon Carbide power metallic oxide semiconductor field effect transistor(MOSFET).Based on an equivalent circuit topology,the model completely describes the static and dynamic device characteristics which include the MOSFET channel current,the nonlinear junction capacitance and the switching behavior.Especially the parasitic elements effect is also considered and studied during the modeling,testing and simulation.The model parameters are extracted based on the experimental measurement data.For convenience,the model is implemented by Verilog-A description language and embedded in the simulation software-Advanced Design System(ADS).The validity and accuracy of the model are validated by the double pulse test under inductor load.The Verification result shows that the modeling job is correct and available for prediction of the switching performance under different conditions.

Improvement on short-circuit ability of SiC super-junction MOSFET with partially widened pillar structure

A novel 1200 V SiC super-junction(SJ)MOSFET with a partially widened pillar structure is proposed and investi-gated by using the two-dimensional numerical simulation tool.Based on the SiC SJ MOSFET structure,a partially widened P-region is added at the SJ pillar region to improve the short-circuit(SC)ability.After investigating the position and doping concentration of the widened P-region,an optimal structure is determined.From the simulation results,the SC withstand times(SCWTs)of the conventional trench MOSFET(CT-MOSFET),the SJ MOSFET,and the proposed structure at 800 V DC bus voltage are 15μs,17μs,and 24μs,respectively.The SCWTs of the proposed structure are increased by 60%and 41.2%in comparison with that of the other two structures.The main reason for the proposed structure with an enhanced SC capability is related to the effective suppression of saturation current at the high DC bias conditions by using a modu-lated P-pillar region.Meanwhile,a good Baliga's FOM(BV^(2)/R_(on))also can be achieved in the proposed structure due to the advantage of the SJ structure.In addition,the fabrication technology of the proposed structure is compatible with the standard epitaxy growth method used in the SJ MOSFET.As a result,the SJ structure with this feasible optimization skill presents an effect on improving the SC reliability of the SiC SJ MOSFET without the degeneration of the Baliga's FOM.