High-Performance La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-δ Electrolyte-Based Direct Raw Brown Coal Fuel Cells

Abstract

The direct carbon solid oxide fuel cell (DC-SOFC) is a potential energy conversion device that cleanly and effectively utilizes various carbon resources to generate electric power through electrochemical conversion. Recently, DC-SOFCs utilizing real-world coal fuel have gained great momentum due to the “dual carbon strategic goals”. Here, we report high-performance La0.9Sr0.1Ga0.8Mg0.2O3‑δ (LSGM) electrolyte-supported DC-SOFCs, by integrating Ag–Gd0.1Ce0.9O2−δ (GDC) as symmetrical electrodes, which enable highly efficient utilization of raw brown coal as fuel. As a comparison, the performances of the conventional yttria-stabilized zirconia (YSZ) electrolyte supported-DC-SOFCs are also investigated. Fueled by raw brown coal, the LSGM-based cells can deliver a maximum power density of 367 mW cm–2 at 850 °C, which is distinctly superior than that of the YSZ-based cells (249 mW cm–2). In addition, stability tests reveal that under a discharge current of 0.15 A, the cell can achieve a discharge time of 4.38 h and a better fuel utilization of 14.8%, indicating that a large current discharge is more propitious for the LSGM-based DC-SOFCs fueled by raw brown coal to achieve higher fuel utilization. This study exhibits the enormous potential of LSGM as an electrolyte material for high-performance direct brown coal fuel cells and provides direction guidance for the optimization of discharge operation of DC-SOFCs directly utilizing brown coal in consideration of fuel utilization.