New design and performance evaluation of 1 kW-class reversible solid oxide electrolysis-fuel cell stack using flat-tubular cells

A new type of solid oxide cell (SOC) stack using fuel-electrode-supported flat-tubular cells has been developed for reversible fuel cell/electrolysis cell (FC/EC) operation at 700 degrees C. The flat-tubular cell in which the end of the tube is plugged and the fuel channels inside the cell are connected through the punched holes reaches the easy scaleup and compact stack volume while sustaining its durability benefits. In this configuration, a metallic cassettetype building block is used to securely mount the cell and serves as the current collector. The power generation and hydrogen production performance are investigated using the I-V test. For a 30-layer stack with 100 cm2 of an active area of a single cell, 1 kW of power generation at +43.7 A and 502 L h-1 of H2 production at -40.0 A are achieved in FC and EC modes, respectively. Additionally, it shows high durability against 500 h of steadystate H2 production as well as against 50 FC/EC cyclic operations with a rapid switching rate (2 h cycle-1). Based on these results, we demonstrate its high potential as a promising flat-tubular r-SOC stack for highly efficient power generation and H2 production.