Power‐to‐Protein: Anion‐Exchange‐Membrane‐Free Solid‐State Electrolysis for Efficient Formic Acid Production and Microbial Protein Synthesis

ABSTRACT Power‐to‐Protein, enabled by porous solid‐state electrolyte (SSE) reactors, harnesses renewable electricity to drive electrochemical CO 2 reduction (CO 2 RR) for the synthesis of bioconsumable nexus molecules that sustain protein‐producing microorganisms. In this study, a cost‐effective porous SSE reactor is developed that eliminates the need for expensive prefabricated anion exchange membranes (AEMs) and advanced catalysts. The design integrates a gas diffusion electrode (GDE) with a cation‐infused sandwich architecture and incorporates a filter paper interlayer between the GDE and SSE layer to enhance selectivity and stability. With commercial Bi, the reactor achieves a single‐pass formic acid concentration of 1.5 m , a Faradaic efficiency of 63.6%, and a stable operation for 150 h at 100 mA cm −2 . Scalability is further demonstrated using a 100 cm 2 prototype. In situ electrochemical analyses reveal that the sandwich‐structured GDE promotes localized alkalinity, thereby enhancing catalytic activity. An integrated Power‐to‐Protein framework is also proposed, coupling electrochemical formic acid production with yeast‐based protein biosynthesis. These findings underscore the potential of biohybrid systems to couple renewable energy‐driven CO 2 valorization with sustainable protein production, advancing the development of circular carbon–energy biomanufacturing pathways.