A nanostructured bifunctional Pd/C gas-diffusion electrode for metal-air batteries

Abstract

Keywords:bifunctional air electrode palladium catalyst metal-air battery A B S T R A C T Designing a bifunctional air electrode which catalyses both the oxygen reduction and oxygen evolution reactions is an essential part of progress towards fully rechargeable metal-air batteries, such as the ironair battery which is environmentally friendly, low cost, and does not suffer risk of thermal runaway like lithium-ion batteries. This paper reports the development of a lightweight carbon-based bifunctional air electrode, catalysed by a small (0.5 mg cm À2 ) loading of 30 wt.% palladium on carbon. The Pd-catalysed air electrode showed good bifunctional activity, with 0.53 V potential difference between oxygen reduction and evolution. The Pd/C air electrode showed improved catalytic activity at high current densities (! 50 mA cm À2) and enhanced durability compared with two commercial Pt/C air electrodes produced by Gaskatel GmbH and Johnson Matthey. A stable oxygen evolution potential was maintained over 1,000 charge-discharge cycles.Crown

A high-performance, bifunctional oxygen electrode catalysed with palladium and nickel-iron hexacyanoferrate

“…Several systems for fundamental studies or as prototypes exist but only few have reached commercial stage. Typical MABs include Zn/O2, [1] Li/O2, [2] Na/O2, [3] K/O2, [4] Mg/O2, [5] Ca/O2, [6] Al/O2, [7] Si/O2, [8] and Fe/O2 [9]. In nonaqueous systems during the discharge cycle, the metal oxidises and its ions migrate through the electrolyte to the gas diffusion electrode (GDE) where they form a solid oxide with the reduced oxygen.…”

“…Typical bifunctional catalysts used in oxygen electrodes include platinum [13] palladium [9] and non-noble metal compound phases, such as perovskites, [ 14 ] spinels, [ 15 , 16 ] and pyrochlores [17]. Perovskite catalysts mixed with high surface area carbon are some of the most promising bifunctional catalyst materials produced to date but reported data varies depending on the type of perovskite and operational conditions.…”

“…The catalyst maintained its catalytic activity and the authors suggested that alternative non-carbon supports need to be developed, such as Nb-doped TiO2 nanoparticles [19] or Ebonex [20]. Gas diffusion electrodes manufactured with perovskite catalysts of type La0.6Ca0.4Co0.8B0.2O3 (B = Mn, Fe, Co, Ni, Cu) developed by Shimizu et al [21] in 7 mol dm -3 KOH reached up to 240 cycles at ±100 mA cm Recently, a bifunctional palladium-based catalyst was produced on a carbon support with exceptionally good corrosion resistance compared with those used in commercial Pt electrodes, [9] circumventing some of the degradation problems associated with repeated cycling of bifunctional oxygen electrodes in alkaline solution. The loading of palladium on this electrode was only 0.5 mg cm -2 , four times lower than a commercial Pt/C electrode.…”

Effect of Gas Diffusion Layer on La0.8Sr0.2CoO3Bifunctional Electrode for Oxygen Reduction and Evolution Reactions in an Alkaline Solution

“…In an effort to address the limitation of the current zinc-air battery, several researches were made to find a catalyst that can effectively catalyze both the ORR and OER; such catalysts are termed bifunctional catalyst. Pt and Pt-Ru catalysts have shown the highest catalytic activity for ORR and OER but, because of their high cost and other drawbacks, non-noble metal catalysts such as perovskites are preferred, among which La1-xSrxCoO3 exhibits the highest catalytic activity [8][9][10][11] .…”

“…The performance of an air electrode is not only affected by a bifunctional catalyst but also requires effective diffusion of O2 through GDL and interaction between catalyst and supporting layer 11) . A GDL should have the ability to transport oxygen from the atmosphere to the catalyst layer and possess low electronic resistance, good electrical conductivity, and excellent wetting characteristics 12,13) .…”