Spray drying as a novel and scalable fabrication method for nanostructured CsH2PO4, Pt-thin-film composite electrodes for solid acid fuel cells

Abstract

Spray drying was explored as a new CsH₂PO₄ nanoparticle synthesis method and a systematic parameter study was conducted to discover the set leading to optimal deposition rate and particle size distribution for applications in solid acid fuel cell electrodes. The nanoparticles were deposited directly onto either a carbon paper current collector or a dense CsH₂PO₄ electrolyte pellet with a deposition rate of 1 mg h⁻¹ cm⁻² measured to be the same order of magnitude as for previously employed electrospray. However, the total nanoparticle production rate is at 165 mg h⁻¹ almost two orders of magnitude higher than the total production rate of electrospray. Novel, high performance solid acid fuel cell electrodes were fabricated by depositing CsH₂PO₄ nanoparticles onto a dense, uniaxially pressed CsH₂PO₄ electrolyte pellet, forming a three dimensional, porous, interconnected nanostructure, and thus providing a large surface area for subsequent Pt thin film deposition via magnetron sputtering. Electrochemical measurements via impedance spectroscopy in a symmetric cell configuration Pt + CsH₂PO₄|CsH₂PO₄|CsH₂PO₄ + Pt show good reproducibility, excellent mass normalized activity as well as stability over a 24 h period.