Nanomaterials and films for polymer electrolyte membrane fuel cells and solid oxide cells by flame spray pyrolysis

Significant progress has been achieved in the development of nanomaterials for polymer electrolyte membrane fuel cells (PEMFC) and solid oxide cells (SOC). However, the limited scalability and multi-step processing of the conventional synthesis routes for the electrocatalysts, their supports and thin functional films in general (e.g., coprecipitation and solid-state synthesis) remain a great challenge for inexpensive production of these energy materials and cells. These drawbacks could be overcome by flame spray pyrolysis (FSP), a simple, rapid, scalable and single step fabrication technique. Here, a comprehensive review on flame-based synthesis and deposition techniques with a major focus on FSP for PEMFCs and SOCs is presented. Flame-made materials of practical importance including Pt, Pt alloys, metal-nitrogen-carbon catalysts, perovskites and catalyst support structures, and their performance are discussed along with challenges and opportunities to bridge the gap between materials research and cell development.