Hygroelectricity is proposed as a means to produce electric power from air by absorbing gaseous or vaporous water molecules, which are ubiquitous in the atmosphere. Here, using a synergy between a hygroscopic bulk graphene oxide with a heterogeneous structure and interface mediation between electrodes/materials with Schottky junctions, we develop a high-performance hygroelectric generator unit with an output voltage approaching 1.5 V. High voltage (e.g., 18 V with 15 units) can be easily reached by simply scaling up the number of hygroelectric generator units in series, enough to drive commercial electronic devices. This work provides insight for the design and development of hygroelectric generators that may promote the efficient conversion of potential energy in the environmental atmosphere to electricity for practical applications.

Green energy has gained growing interest due to the increasing serious environmental pollution and energy crisis. Herein, we developed an all-region-applicable moist-electric generator (MEG) based on a graphene oxide composite to harvest energy from atmospheric moisture over a wide range of temperature (−25 °C to 50 °C) and relative humidity (RH, 5–95%). It could continuously deliver a comparatively high open-circuit voltage of ∼0.6 V for more than 120 hours under an ambient environment with a small device size of only about 0.1 cm⁻². The electric output could be enhanced to directly power many commercial electronic devices without the need for external rectifying circuits and capacitors. The experiments and simulations suggest that the spontaneous absorption of water molecules and the directional migration of ions within the composite mainly contribute to the electricity generation. This study provides new insights for the generation of sustained green energy from atmospheric moisture in arbitrary ambient environments, holding immense promise for widespread practical applications in complex environments.

Solar powered clean water production has been considered a favorable way to address the problem of the global water shortage. Recently, the interfacial solar-steam generation system has greatly improved water evaporation by localizing the solar energy at an advanced solar-thermal conversion material interface. However, the specific water productivity (SWP) is still far away from a satisfactory level due to the strong mutual interference between the incident sunlight and the generated water vapor, which causes a huge loss in energy and in turn restrains the final efficiency in water evaporation and collection. SWP is the water collection per solar radiation area per hour, which reflects the actual solar efficiency for water production and a key concern in desalination. Herein, we report a rational Janus-interface solar-steam generator (J-SSG), which separates the water evaporation and the solar-thermal conversion on the two sides of the film generator. This J-SSG demonstrates a water evaporation rate of up to 2.21 kg m⁻² h⁻¹ under 1 sun in a large area of 100 cm². More importantly, a record high SWP of 1.95 kg m⁻² h⁻¹ is realized in a simple system, and the SWP efficiency corresponding to the ratio of SWP to evaporation rate is as high as 88%. In an outdoor test (Beijing, solar energy ∼15 MJ m⁻² day⁻¹), 10 L purified water per square meter have been easily achieved. This Janus-interface engineering of the solar-steam generator provides a novel strategy and solution for solar powered water production of practical significance.

Spontaneous electrical potential is essential and widely exists in living cell membranes of organism, and could provide a novel power-supply system without external stimuli. However, the highly complex and delicate biological structures have restricted the huge electrical energy in practical applications. Herein, we report the spontaneous electric generation of a functional groups-reconfigured graphene oxide membrane in ambient atmosphere, which was prepared by a directionally-induced thermal reduction strategy. The as-prepared asymmetric porous graphene oxide membrane (a-GOM) with a size of only 4 mm² can proactively generate a sustained electrical voltage of up to 450 mV in air without the need of external stimuli such as mechanical movement, light, heat, and liquid water. Of practical importance, it is easy to reach a high voltage of more than 10 V by simple series stacking of a-GOM units, powering many commercial electronic components such as liquid crystal displays (LCD) and light-emitting diodes (LED). In addition, flexible and foldable power generation devices having soft package technology (being used for the fabrication of commercial lithium-ion batteries) are achievable on the basis of the assembly of a-GOM units.

Environment-adaptive power generation can play an important role in next-generation energy conversion. Herein, we propose a moisture adsorption-desorption power generator (MADG) based on porous ionizable assembly, which spontaneously adsorbs moisture at high RH and desorbs moisture at low RH, thus leading to cyclic electric output. A MADG unit can generate a high voltage of ~0.5 V and a current of 100 μA at 100% relative humidity (RH), delivers an electric output (~0.5 V and ~50 μA) at 15 ± 5% RH, and offers a maximum output power density approaching to 120 mW m⁻². Such MADG devices could conduct enough power to illuminate a road lamp in outdoor application and directly drive electrochemical process. This work affords a closed-loop pathway for versatile moisture-based energy conversion.