Imperial College London

Professor Nigel Brandon OBE FREng

Faculty of Engineering

Dean of the Faculty of Engineering
 
 
 
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Contact

 

+44 (0)20 7594 8600n.brandon Website

 
 
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Location

 

2.06Faculty BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Chen:2019:10.1039/c9nr06740j,
author = {Chen, J and Wang, X and Boldrin, P and Brandon, NP and Atkinson, A},
doi = {10.1039/c9nr06740j},
journal = {Nanoscale},
pages = {17746--17758},
title = {Hierarchical dual-porosity nanoscale nickel cermet electrode with high performance and stability},
url = {http://dx.doi.org/10.1039/c9nr06740j},
volume = {11},
year = {2019}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - Nano-structured metal-ceramic materials have attracted attention to improve performance in energy conversion applications. However, they have poor long-term stability at elevated temperatures due to coarsening of the metal nanoparticles. In this work we show that this can be mitigated by a novel design of the nano-structure of Ni cermet fuel electrodes for solid oxide cells. The strategy is to create a dual porosity microstructure, without the use of fugitive pore-formers, with micron-size pores to facilitate gas transport and nanoscale pores to control nano-particle coarsening. This has been achieved using a continuous hydrothermal synthesis and two-stage heat treatments to produce electrodes with micron size agglomerates of nano-structured porous Ni-Yttria-Stabilised-Zirconia (YSZ). This unique hierarchical microstructure combines enhanced electrochemical reaction in the high activity (triple phase boundary density 11 μm-2) nanoscale regions with faster gas diffusion in the micron-sized pores. The electrodes are aged at 800 °C in humidified 5% H2-N2 for up to 600 h. The electrochemical reaction resistance is initially 0.17 Ω cm2 but later reaches a steady long-term value of 0.15 Ω cm2. 3-D reconstruction of the electrodes after 10 h and 100 h of ageing reveals an increase in YSZ network connectivity and TPB percolation. This improvement is well-correlated to the 3-D tomography parameters using a physical model adapted from mixed conducting SOC air electrodes, which is also supported, for the first time, by numerical simulations of the microstructural evolution. These also reveal that in the long term, nickel coarsening is inhibited by the nanoscale entanglement of Ni and YSZ in the hierarchical microstructure.
AU - Chen,J
AU - Wang,X
AU - Boldrin,P
AU - Brandon,NP
AU - Atkinson,A
DO - 10.1039/c9nr06740j
EP - 17758
PY - 2019///
SN - 2040-3364
SP - 17746
TI - Hierarchical dual-porosity nanoscale nickel cermet electrode with high performance and stability
T2 - Nanoscale
UR - http://dx.doi.org/10.1039/c9nr06740j
UR - https://www.ncbi.nlm.nih.gov/pubmed/31549698
UR - http://hdl.handle.net/10044/1/73608
VL - 11
ER -