Designing of low-temperature high performance semiconductor ionic fuel cells based on molten hydroxide percolation network

Abstract

A low-temperature high performance semiconductor ionic membrane fuel cell (SIMFC) featuring a γ-Al2O3/NCAL symmetrical electrode and a ceria-based Li0.85Na0.15OH/Mg0.1Al0.2Ce0.7O2-δ (LNCMA) electrolyte has been designed. This device attains a maximum power density (MPD) of 1111 mW/cm2 and demonstrates stability for nearly 40 h at 550 ℃. Additionally, the system remains operational at 350 ℃, delivering an excellent MPD of 114 mW/cm2. The amazing research can be attributed to a molten network of hydroxide that serves as a highway for oxygen ion interface conduction, leading to an enhancement in the ionic conductivity and a reduction in ohmic impedance of the SIMFC. In the testing environment of this newly developed SIMFC device, the γ-Al2O3/NCAL electrode provides a protective effect on LiOH, enabling higher concentrations of molten LiOH to be retained and percolated into the electrolyte. Subsequently, the composite Li0.85Na0.15OH directly introduced into LNCMA melts and readily connects with LiOH from the anode, forming a molten network. As a result, the SIMFC, designed based on the concept of the molten hydroxide percolation network, achieves improved fuel cell performance and enables the operation of the SIMFC even at 350 ℃. This study showcases a convenient method for constructing a molten hydroxide percolation network, which provides the necessary low-temperature conductivity required for SIMFCs.