 Low-rate and limited duration are major challenges in photobiological hydrogen production. Here, the authors coat algal cells with a concentrically arranged shell comprising an ultrathin Fe3, doped polypyrrole in a layer, an out-exoskeleton of CaCO3, and achieve sustainable H2 production for over 200 days. This article was authored by Dijun Xu, Jero Aichi, Shengliang Wang, and others.