Flexible Solid‐State Direct Ethanol Fuel Cell Catalyzed by Nanoporous High‐Entropy Al‐Pd‐Ni‐Cu‐Mo Anode and Spinel (AlMnCo)3O4 Cathode

As in many other electrochemical energy‐converting systems, the flexible direct ethanol fuel cells rely heavily on high‐performance catalysts with low noble metal contents and high tolerance to poisoning. In this work, a generic dealloying procedure to synthesize nanoporous multicomponent anodic and cathodic catalysts for the high‐performance ethanol fuel cells is reported. On the anode side, the nanoporous AlPdNiCuMo high‐entropy alloy exhibits an electrochemically active surface area of 88.53 m2 g−1Pd and a mass activity of 2.67 A mg−1Pd for the ethanol oxidation reaction. On the cathode side, the dealloyed spinel (AlMnCo)3O4 nanosheets with no noble metals demonstrate a comparable catalytic performance as the standard Pt/C for the oxygen reduction reaction, and tolerance to high concentrations of ethanol. Equipped with such anodic and cathodic catalysts, the flexible solid‐state ethanol fuel cell is able to deliver an ultra‐high energy density of 13.63 mWh cm−2 with only 3 mL ethanol, which is outstanding compared with other similar solid‐state energy devices. Moreover, the solid‐state ethanol fuel cell is highly flexible, durable and exhibits an inject‐and‐run function. Flexible solid‐state direct ethanol fuel cells show great promise in various applications. In this work, nanoporous high‐entropy AlPdNiCuMo face‐centered cubic alloy and (AlMnCo)3O4 spinel oxides are prepared and used as anodic and cathodic catalysts to enhance fuel cell performance. A high energy density of 13.63 mWh cm−2, flexibility, and inject‐and‐run function are achieved.