Biomass-derived nanostructured coatings based on cellulose nanofibers-melanin hybrids toward solar-enabled multifunctional energy management

Solar-to-thermal conversion is a direct and efficient way to –convert renewable and green sunlight to manageable thermal energy for diverse applications from steam production, energy harvest to personal thermal management. However, developing biomass-derived functional materials with eco-friendly, low-cost, and extensible features remains a challenge. Here, a cost-effective, scalable, biodegradable, and multifunctional nanocomposite was designed for solar-to-thermal applications. Through balancing the photothermal and water-absorbing capacities, the designed solar evaporator can demonstrate an efficient evaporation rate of 1.23 kg m−2 h−1 under 1 sun. Meanwhile, solar irradiation can further boost the directional water flow process, resulting in a remarkable improvement of generated voltage from the initial 410–515 mV under 1 sun. Thus, the as-prepared nanocomposites displayed an excellent comprehensive performance, which was superior to the majority of the previously reported non-biomass and other biomass materials. Furthermore, a wearable personal thermal management device was designed to simultaneously realize the electrical response of solar intensity and fast heating. As a proof of concept, a thermal managing house system enabled by solar energy was implemented to achieve an effective and eco-friendly temperature control without excessive energy consumption.