Abstract:
Solid oxide fuel cells (SOFCs) have attracted much attention in the area of power generation due to their high energy efficiency and low pollution emissions. However, when complex fuels such as carbon or hydrocarbons are used directly, traditional SOFCs with solid anodes face challenges such as poor fuel transportation, coking and carbon deposition in anode, which has always been a critical issue that researchers continue to tackle. Liquid metal anode (LMA) is a new type of SOFC anode with self-repairing and anti-coking and carbon deposition properties, which exhibits obvious advantages in the conversion of carbon and hydrocarbon fuels. This paper first briefly introduces the operating principle of liquid metal anodes, then the reaction characteristics of several common types of existing liquid metal electrodes are summarized. Among them, the metal oxide corresponding to the liquid antimony anode is in a liquid state at the conventional operating temperature of SOFC (700−800 ℃), which allows for efficient oxygen transport within the electrode through natural convection driven by density differences. Therefore, the liquid antimony anode exhibits excellent reaction characteristics, which is the most promising liquid metal electrode for converting various carbon-based fuels. Then, the conversion mechanism of solid carbon fuels and various types of hydrocarbon fuels in liquid antimony anodes is summarized, and the catalytic effect and impurity tolerance characteristics of liquid metal anodes is reviewed. Finally, considering that the metal-metal oxide self-circulation in the liquid metal anode will cause theoretical efficiency loss, this paper conducts theoretical calculations and proposes an autothermal reforming strategy based on liquid metal anodes. Based on this, the liquid metal anode SOFC is conceptualized as an "electrochemical reformer" for combined gas and electricity production, then the generated H
2 and CO are introduced into a downstream conventional SOFC, enabling the cascade utilization of energy. This approach holds promise for developing a comprehensive power generation technology with wide fuel adaptability and high energy efficiency.