Flexible　and　all-solid-state　zinc-air　batteries　(ZABs)　are　highly　useful　and　also　in　demand　due　to　their　theoretical　high　energy　densities　and　special　applications.　The　limitation　in　their　performance　arises　due　to　their　catalyst-coated　cathode　electrodes　in　terms　of　catalytic　activity　and　stability　as　well　as　cost.　In　this　paper,　a　novel　and　environmentally　friendly　activation　strategy　is　developed　to　activate　the　carbon　cloth　(CC)　for　the　electrodes.　The　activated　CC　serves　as　a　catalyst-free　air　cathode　with　high　conductivity,　excellent　mechanical　strength,　and　flexibility,　in　addition　to　low　cost.　The　strategy　is　performed　by　simply　electro-oxidizing　and　electroreducing　CC　under　ultrahigh　direct　current　(DC)　voltage　in　a　diluted　NH4Cl　aqueous　electrolyte.　It　is　found　that　the　electro-oxidation　not　only　results　in　the　formation　of　a　graphene-like　exfoliated　carbon　layer　on　the　surface　of　CC　but　also　induces　the　incorporation　of　oxygen-containing　groups　and　doping　of　nitrogen　and　chloride　atoms.　After　the　electroreduction,　the　π-conjugated　carbon　network　of　CC　is　partially　restored,　leading　to　the　recovery　of　electroconductivity.　Such　an　electroactivated　CC　shows　excellent　oxygen　reduction　reaction　activity.　The　aqueous　flexibility　and　all-solid-state　ZABs　are　assembled　using　such　an　electroactivated　CC　cathode　without　any　catalyst　loading.　Both　ZABs　can　achieve　good　durability　and　deliver　high　peak　power　density　and　an　energy　density　as　high　as　690　Wh　kg−1,　demonstrating　the　excellent　potential　of　this　electroactivated　CC　in　practical　devices.　©　2022　The　Authors.　Carbon　Energy　published　by　John　Wiley　&　Sons　Australia,　Ltd　on　behalf　of　Wenzhou　University.