Electrophoretic deposition of YSZ thin-film electrolyte for SOFCs utilizing electrostatic-steric stabilized suspensions obtained via high energy ball milling

This manuscript describes a facile alternative route to make thin-film yttria-stabilized zirconia (YSZ) electrolyte by liquid-phase assisted electrophoretic deposition utilizing electrostatic-steric stabilized YSZ suspension followed by sintering. Very fine YSZ particles in ball-milled suspension facilitate their sustained dispersion through electrostatic mechanism as evidenced by their higher zeta potentials. Binder addition into the ball-milled suspension is also demonstrated to contribute complementary steric hindrance effects on suspension stability. As the consequence, the film quality and sinterability improve in the sequence of film made from non ball-milled suspension, film made from ball-milled suspension and film made from ball-milled suspension with binder addition. The specific deposition mechanisms pertaining to each suspension are also postulated and discussed below. A very thin dense electrolyte layer of ∼10 μm can be achieved via electrophoretic deposition route utilizing ball-milled suspension and binder addition. This in turn, makes the electrolyte resistance a more negligible part of the overall cell resistance. Further on, we also tested the performance of SOFC utilizing as-formed 10 μm YSZ electrolyte i.e. YSZ-NiOYSZLSM (La_0.8Sr _0.2MnO_3-δ), whereby a maximum power density of ∼850 mW cm^-2 at 850 °C was demonstrated.