Preparation and characterization of Ni–PTFE plate as an electrode for alkaline fuel cell: Effects of conducting materials on the performance of electrode

Abstract

Polytetrafluoroethylene (PTFE) fine particles (25 μm) were coated with 29–43 wt% Ni using electroless Ni plating. The Ni-plated PTFE (Ni–PTFE) particle conductivity increased concomitantly with increasing Ni contents. For 43 wt% Ni particles, the conductivity was about 300 S m −1. After pressing the particles into plates with 300 kg cm −2 pressure and subsequent heat treatment at 350 °C, acetylene black (AB) and graphite particles were introduced into the plates as conducting materials to elucidate effects on electrical conductivity and gas permeability. Plates containing AB (1.3 wt%) and graphite (5 wt%) respectively showed 1.25 and 1.5 times higher conductivity than the original Ni–PTFE plate did. The AB particles particularly caused pore volume expansion at the 0.1–1.0 μm size range in Ni–PTFE plates. The expanded total pore volume (0.159 cm 3 g −1) of Ni–PTFE plate with AB particles improved gas permeability, which increased the electrode life performance (25% up for 24 h) in alkaline fuel cells (AFCs). The current density of Ni–PTFE electrode containing AB particles was about 4.5 times than that of original Ni–PTFE electrode.