Investigation of Rapid, Moderate Temperature Change Thermal Cycles of a Micro-Tubular Flame-Assisted Fuel Cell

Abstract

Despite many efforts and improvements over the last few decades, two of the major challenges facing solid oxide fuel cells (SOFCs) are slow heating rates to operating temperature (typically < 5 °C · min−1) and a limited ability to thermal cycle (<200 cycles). Recently, a novel hybrid setup that combines a fuel-rich combustion reformer with a SOFC was developed and utilized to investigate rapid heating, cooling, and thermal cycling of a micro-tubular SOFC. In this work, 3000 moderate thermal cycles are conducted at a heating rate exceeding 140 °C · min−1 and a cooling rate that exceeded 100 °C · min−1. The open-circuit voltage (OCV) was analyzed over the 150 h test, and a low degradation rate of ∼0.0008 V per 100 cycles per fuel cell was observed in the absence of the current collector degradation. Unlike a previous test, which was conducted at lower temperatures, significant degradation of the current collector was observed during this test. Electrochemical impedance spectroscopy shows that degradation in the SOFC was due to increases in ohmic losses, activation losses at the cathode, and increased concentration losses.