Fabrication of metal-supported solid oxide fuel cells by sinter-joining method with silver bonding layer

Abstract

Solid oxide fuel cell (SOFC) is an energy conversion device which generates electricity from hydrogen. SOFC is attracting attentions because of its high energy conversion efficiency and low material cost. For transportation applications, high mechanical strength is required, which makes ceramic-based SOFC unsuitable. To overcome this limitation, metal-supported SOFC has been proposed. In this work, metal-supported SOFCs are developed by bonding metal substrates to ceramic cells with silver bonding paste. By using silver as bonding material, bonding was performed at temperature lower than 950°C in air atmosphere, which enables full sintering of cathode. Furthermore, electrical conductivity and thermal conductivity are improved, leading to lower ohmic resistance and better temperature distribution of metal-supported cells. As a result, 5 × 5 cm2 metal-supported SOFCs with power density of 433 mW cm-2 at 800°C were fabricated. The metalsupported SOFCs showed 10 times higher mechanical strength than conventional ceramic cells.