Nanoplating SnO2 thin-film on MXene-based sponge for stable and efficient solar energy conversion

The poor oxygen resistance of MXene-based materials greatly limits their large-scale applications in solar-energy storage and conversion. Herein, we report a MXene-based sponge nanoplated by SnO2 thin-film (SnO2-SPM) for stable solar-driven simultaneous water purification and electricity generation. Such SnO2 thin-film nanoplating strategy avoids the MXenes' surface oxidation by isolating them from O2, thus ensuring the high-efficient and long-term light-to-heat conversion. A stable water output (1.41 kg•m−2•h−1, reused 30 d) with a thermal efficiency of ~84.8% was achieved under 1-sun in various wastewaters (e.g., saline waters, strong acid, alkali solutions and heavy metal wastewaters), highlighting the corrosion resistance and antifouling functionality. Steady power generation (~3.6 V) for 100-hours during water purification further demonstrates the reliability of this strategy. The COMSOL simulation help us to understand how different thickness of SnO2 thin-film influences the surface-temperature distribution of SnO2-SPM. This work lays the foundation for MXenes' appliation in long-term electricity and clean-water production.