An Up-scalable, Infiltration-Based Approach for Improving the Durability of Ni/YSZ Electrodes for Solid Oxide Cells

In solid oxide electrolysis cells (SOECs), considerable degradation of the Ni/YSZ electrode during long-term electrolysis operation at high current densities (-1 A cm(-2) or above) has been an ongoing challenge. In this work we report on a method alleviating the problem based on infiltrating nano-sized electrocatalysts into the Ni/YSZ electrode of a full cell after it has been reduced in a "one-atmosphere-reduction" process. The performance and durability of infiltrated and non-infiltrated cells are evaluated at full test-cell size of 4 x 4 cm(2) level. The infiltrated cell exhibits significantly enhanced durability when operated for steam electrolysis at 750 degrees C under high current densities, with cell voltage degradation rates of 0.028 V kh(-1) (2.0% kh(-1)) for 800 h at -1.25 A cm(-2) and 0.010 V kh(-1) (0.8% kh(-1)) for 300 h at -1.00 A cm(-2). These degradation rates are similar to 14 times and similar to 25 times smaller than those of the non-infiltrated cell, respectively. The infiltrated cell also shows superior durability to the non-infiltrated cell during reversible operation. These results demonstrate the great potential of boosting the durability of state-of-the-art Ni/YSZ fuel electrodes for electrolysis operation via this infiltration-based approach. (c) 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.