Highly salt-resistant and all-weather solar-driven interfacial evaporators with photothermal and electrothermal effects based on Janus graphene@silicone sponges

Highlights: • Highly salt-resistant and all-weather solar evaporators with photothermal and electrothermal effects are developed. • The evaporators feature a high evaporation rate of 6.53 kg m⁻² h⁻¹ under 1 sun. • The evaporators exhibit long-term excellent salt-resistance. • The evaporators show high clean water collection rates of 21.92 kg m⁻² d⁻¹ (indoor) and 9.65 kg m⁻² d⁻¹ (outdoor). Solar-driven interfacial evaporators are very promising for obtaining clean water, but suffer from serious performance degradation due to salt-fouling, low evaporation rate under weak illumination and low clean water collection rate. Here, we report highly salt-resistant and all-weather evaporators with photothermal and electrothermal effects based on the Janus graphene@silicone sponges with opposing wettability. The evaporators achieve a remarkable high evaporation rate of 6.53 kg m⁻² h⁻¹ for 3.5 wt% NaCl solution under 1 sun illumination with a 5 V solar cell as compensation owing to their high solar absorption, low thermal conductivity, unique Janus structure and synergetic photothermal and electrothermal effects. Even in gloomy and dark environments, the evaporators could still generate vapor (1.51 kg m⁻² h⁻¹). Moreover, the evaporators feature long-term excellent salt-resistance, e.g., > 10 d continuous evaporation in 10 wt% NaCl solution without performance degradation and salt precipitation, because of ultrafast water supply and salt diffusion in the macroporous superhydrophilic shell. Furthermore, the evaporators show high clean water collection rates of 21.92 kg m⁻² d⁻¹ (1 sun-9 h/0 sun-15 h + 5 V, indoor) and 9.65 kg m⁻² d⁻¹ (natural sun light + 5 V, outdoor). This study offers a new approach for efficiently obtaining clean water via solar desalination.