Polyoxometalates for continuous power generation by atmospheric humidity

Atmospheric humidity is a sustainable low-value energy widely existing in natural environment, which is a promising candidate to solve the noncontinuous and low efficiency of low-value energy power generation. Here the mono-substituted Dawson-type polyoxometalates are constructed to be highly dispersed organic ammonium-polyoxoanion clusters and are assembled into thin films power generators with micropores, working in atmospheric humidity. The optimal polyoxometalates generator with the thickness of 7.2 μm and the area of 0.36 cm² produces a voltage of 0.68 V and a current density of 19.5 μA·cm⁻² under simulated natural environment, and works continuously and stably under almost all-natural environments (humidity 10%–90%). The highly dispersed polyoxometalate nanoclusters can form microporous in polyoxometalate films to effectively absorb atmospheric humidity and spontaneously form distribution gradient of water, which is the structural basis of power generation. The continuous power generation may be maintained by the effective adsorption and utilization of H₂O, the huge electrostatic field of organic ammonium-polyoxoanion clusters, and the reasonably designed polyoxometalates containing inorganic small ions with high mobility. It is the first humidity generator designed with polyoxometalates, which may provide a new research direction for polyoxometalates in sustainable utilization of low-value energy.