Investigation of H_2S Solid Oxide Fuel Cells with a Li_2SO_4-based Proton-conducting Membrane

摘要

A H_2S solid oxide fuel cell with a configuration of H_2S, (MoS_2 + NiS+ Ag) /Li_2SO_4 + Al_2O_3/ (NiO+ Ag), air was fabricated and studied for production of power and for desulfurization of a fuel gas process stream. The cell was run at typical temperatures (600 ～ 650℃) and ambient pressure. The electrochemical performance of a fuel cell can be limited by electrolyte membrane formula, electrode materials and operating temperatures. The Li_2SO_4-based proton-conducting membrane incorporating Al_2O_3 and little boric (H_3BO_4) enhances mechanical and electrical properties, improves the membrane compactivity and cell performance. The suitable formula of Li_2SO_4 to Al_2O_3 is 3 ～ 4: 1 by weight, and the suitable boric amount added is 2%～5% (wt), respectively. Composite anodes based on metal sulfides with Ag powder and electrolyte behaved well and stably in H_2S stream, and composite cathodes based mainly on nickel oxide with Ag powder and electrolyte had superior performance to Pt catalyst for removal of H_2S. The maximum power density of up to 70 mW·cm~(-2) and current density of as high as 180 mA·cm~(-2) were obtained at 650℃. However, the long-term cell stability remains to be investigated.