Fiber-shaped　supercapacitors　(FSSCs)　with　high　rate-capability,　light　weight,　and　knittability　are　promising　members　of　future　flexible　energy　storage　clubs.　However,　limited　by　the　trade-off　between　capacity　density　and　transport　kinetics　of　fiber　electrodes,　the　FSSC　often　delivers　an　insufficient　energy　density　and　power　density,　suppressing　its　practical　application　prospects.　Here,　an　aqueous　asymmetric　FSSC　is　developed,　which　is　composed　of　highly　conductive　positive　and　negative　electrodes　with　coordinated　pseudocapacitive　characteristics,　achieving　a　balance　of　electrochemical　performances.　Benefiting　from　the　wide　voltage　window　and　quick　ion　transport　kinetics　in　the　gel　electrolyte,　this　asymmetric　fiber　device　gives　an　ultrahigh　energy　density　of　41　mW　h　cm−3　and　a　high　power　density　of　725　mW　cm−3,　outperforming　most　state-of-the-art　aqueous　asymmetric　or　symmetric　FSSCs.　Moreover,　it　can　power　commercial　electronic　devices　with　excellent　flexibility　and　bendability,　demonstrating　a　promising　avenue　for　fiber-based　energy　storage　devices　with　great　practical　importance.　©　2022　The　Royal　Society　of　Chemistry.