Carbon-based　flexible　fiber-based　supercapacitors　(FFSCs)　are　promising　power　sources　for　portable　and　wearable　electronics,　but　their　applications　are　limited　by　low　energy　density　due　to　a　lower　specific　capacitance　of　common　carbon　materials.　We　fabricated　ternary　all-carbon　fiber　electrodes　(N-GQD/GH/CF)　with　improved　electrochemical　performance.　In　this　structure,　graphene　hydrogel　(GH)　was　grown　on　carbon　fibers　(CFs)　to　form　a　3D　interconnected　porous　network　(GH/CF),　and　nitrogen-doped　graphene　quantum　dots　(N-GQDs)　with　high　pseudocapacitive　activity　were　electrodeposited　into　the　GH/CF　network.　The　ternary　N-GQD/GH/CF　hybrid　electrode　delivered　a　volumetric　capacitance　of　93.7　F　cm(-3)　at　20　mA　cm(-3),　which　was　around　7　times　higher　than　that　of　the　GH/CF,　while　the　capacitance　retention　after　5000　cycles　reached　87.9%,　which　was　only　a　little　lower　than　that　of　the　GH/CF　electrode　(90.2%).　It　indicates　the　introduction　of　N-GQDs　drastically　improves　the　capacitance　of　the　FFSCs　without　sacrificing　the　cycle　stability.　All-carbon　asymmetric　FFSCs　were　assembled　using　N-GQD/GH/CF　as　positive　electrode　and　GH/CF　as　negative　electrode.　The　assembled　FFSCs　exhibited　a　high　energy　density　of　3.6　mW　h　cm(-3)　at　power　density　of　35.6　mW　cm(-3)　owing　to　the　wider　potential　window　(2　V)　and　the　higher　volumetric　capacitance　as　well　as　excellent　flexibility　and　cycling　stability.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.