Reducing critical raw material use in commercial solid oxide fuel cells
using vertically aligned thin-film cathodes with enhanced long-term
stability
Abstract
Solid oxide fuel cells (SOFCs) are widely presented as a sustainable
solution to future energy challenges. Nevertheless, SOFCs presently rely
on significant use of several critical raw materials to enable optimised
reaction kinetics at the device electrodes. This challenge can be
addressed through the use of thin-film electrode materials, however this
is typically accompanied by complex device fabrication procedures as
well as poor mechanical and chemical stability. In this work, we conduct
a systematic study of a range of promising thin-film electrode materials
based on vertically aligned nanocomposite (VAN) thin films. We
demonstrate low area specific resistance (ASR) values of 0.44 cm2 at
650° C can be achieved using (La0.60Sr0.40)0.95Co0.20Fe0.80O3 -
(Sm2O3)0.20(CeO2)0.80 (LSCF-SDC) thin films, which are also
characterised by a low degradation rate, approximately half that of
planar LSCF thin films. We then integrate these LSCF-SDC VAN films
directly with commercial anode supported half cells through a single
step deposition process. The resulting cells exhibit peak power density
of 0.47 W/cm2 at 750° C, competitive with 0.64 W/cm2 achieved for the
same cells operating with a bulk LSCF cathode despite 99.5% reduction
in cathode critical raw material use. Therefore, the present work marks
a valuable step towards the sustainable proliferation of SOFC
technology.