LiNiFe-based layered structure oxide and composite for advanced single layer fuel cells

•Single layer fuel cell (SLFC) based on layer structured oxide Fe doped LiNiO2 (LNF).•Electrical properties and electrode catalytic activity are investigated.•Balanced ionic and electronic conductivity of LNF-SDC composite.•Super-performance of SLFC based on LNF-SDC composite.•2.76 times improvement of power output of LNF-SDC based SLFC over LNF based SLFC.

A layered structure metal oxide, LiNi0.1Fe0.90O2−δ (LNF), is explored for the advanced single layer fuel cells (SLFCs). The temperature dependent impedance profiles and concentration cells (hydrogen concentration, oxygen concentration, and H2/air atmospheres) tests prove LNF to be an intrinsically electronic conductor in air while mixed electronic and proton conductor in H2/air environment. SLFCs constructed by pure LNF materials show significant short circuiting reflected by a low device OCV and power output (175 mW cm−2 at 500 °C) due to high intrinsic electronic conduction. The power output is improved up to 640 and 760 mW cm−2, respectively at 500 and 550 °C by compositing LNF with ion conducting material, e.g., samarium doped ceria (SDC), to balance the electronic and ionic conductivity; both reached at 0.1 S cm−1 level. Such an SLFC gives super-performance and simplicity over the conventional 3-layer (anode, electrolyte and cathode) FCs, suggesting strong scientific and commercial impacts.