# Ammonia-fed reversible protonic ceramic fuel cells with Ru-based catalyst

## TL;DR

This paper presents a new ammonia-fed fuel cell that can generate power and produce ammonia efficiently, offering a sustainable energy solution.

## Contribution

The study introduces a novel Ru-based catalyst and a high-performance protonic ceramic fuel cell design for ammonia utilization.

## Key findings

- The RePCFC achieved a maximum power of 877 mW cm−2 at 650 °C using ammonia as fuel.
- Stable operation was demonstrated for 1250 h at 600 °C under ammonia fuel.
- Ammonia production rates reached 2.1 × 10−6 mol NH3 cm−2 s−1 at 12.5 bar with H2 from electrolysis and recycling.

## Abstract

The intermediate operating temperatures (~400–600 °C) of reversible protonic ceramic fuel cells (RePCFC) permit the potential use of ammonia as a carbon-neutral high energy density fuel and energy storage medium. Here we show fabrication of anode-supported RePCFC with an ultra-dense (~100%) and thin (4 μm) protonic ceramic electrolyte layer. When coupled to a novel Ru-(BaO)2(CaO)(Al2O3) (Ru-B2CA) reversible ammonia catalyst, maximum fuel-cell power generation reaches 877 mW cm−2 at 650 °C under ammonia fuel. We report relatively stable operation at 600 °C for up to 1250 h under ammonia fuel. In fuel production mode, ammonia rates exceed 1.2 × 10−8 NH3 mol cm−2 s−1at ambient pressure with H2 from electrolysis only, and 2.1 × 10−6 mol NH3 cm−2 s−1 at 12.5 bar with H2 from both electrolysis and simulated recycling gas.

Ammonia-fed protonic ceramic fuel cells could be a more sustainable alternative than their hydrogen-fed counterparts. In this work, the authors couple an reversible ammonia catalyst with a protonic ceramic electrochemical cell, enabling cracking of ammonia into H2 and N2 for fuel-cell mode operation, as well as synthesis of ammonia from H2O and N2 in electrolysis mode operation.