Nowadays,　self-charging　devices　using　clean　energy　have　raised　the　potential　of　portable　and　wearable　power　generators.　Herein,　a　novel　moisture-induced　self-powered　device　based　on　metal–air　redox　reaction　has　been　designed　which　can　work　under　normal　humidity　conditions.　Through　bridging　two　asymmetric　electrodes　including　a　carbon　nanotube/polyaniline　composite　electrode　and　a　metal　electrode　by　filter　paper　with　CaCl2,　the　1D　planar　device　can　be　simply　fabricated.　A　single　device　can　provide　an　open-circuit　voltage　of　over　1.3　V　under　normal　humidity　(40%)　within　5　min　(the　maximum　can　be　up　to　1.42　V　at　80%　humidity)　and　the　harvesting　energy　can　be　stored　effectively.　The　device　possesses　great　circularity　and　stability　which　can　maintain　steady　and　consistent　output　over　at　least　6　months.　Due　to　the　microelectrolyte,　this　device　can　prevent　harmful　leakage　or　deformation　of　the　electrolyte　completely.　What　is　more,　the　device　shows　good　extendibility.　Three　single　devices　in　series　using　common　electrodes　can　light　up　two　light-emitting　diodes.　Besides　its　application　potential　in　self-powered　portable　and　wearable　electronics,　this　device　can　provide　a　reference　for　utilization　in　medical　devices　due　to　the　response　signals　under　breath　with　different　frequencies.　©　2023　Wiley-VCH　GmbH.