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

Abstract 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 m 2 g −1 Pd and a mass activity of 2.67 A mg −1 Pd for the ethanol oxidation reaction. On the cathode side, the dealloyed spinel (AlMnCo) 3 O 4 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.