Simultaneous Solar‐driven Steam and Electricity Generation by Cost‐effective, Easy Scale‐up MnO2‐based Flexible Membranes

Harvesting solar energy in an effective manner for steam and electricity generation is a promising technique to simultaneously cope with the energy and water crises. However, the construction of efficient and easy scale‐up photothermal materials for steam and electricity cogeneration remains challenging. Herein, we report a facile and cost‐effective strategy to prepare MnO 2 ‐decorated cotton cloth (MC x ). The wide adsorption spectrum and excellent photothermal conversion ability of the in situ‐formed MnO 2 nanoparticles make the MC x to be advanced photothermal materials. Consequently, the hybrid device integrated with MC x as the photothermal layer and the thermoelectric (TE) module for electricity power conversion exhibits an extremely high evaporation rate of 2.24 kg m −2 h −1 under 1 kW m −2 irradiation, which is ranked among the most powerful solar evaporators. More importantly, during solar evaporation, the hybrid device produces an open‐circuit voltage of 0.3 V and a power output of 1.6 W m −2 under 3 Sun irradiation, and outperforms most of the previously reported solar‐driven electricity generation devices. Therefore, the integrated device with synergistic solar‐thermal utilization opens up a green way toward simultaneous solar vapor and electric power generation in remote and resource‐constrained areas.