Fabricating　of　high　performance　electrodes　by　a　sustainable　and　cost　effective　method　is　essential　to　the　development　of　vanadium　redox　flow　batteries　(VRFBs).　In　this　work,　an　effective　strategy　is　proposed　to　deposit　carbon　nanoparticles　on　graphite　felts　by　hydrothermal　carbonization　method.　This　in-situ　method　minimizes　the　drop　off　and　aggregation　of　carbon　nanoparticles　during　electrochemical　testing.　Such　integration　of　felts　and　hydrothermal　carbons　(HTC)　produces　a　new　electrode　that　combines　the　outstanding　electrical　conductivity　of　felts　with　the　effective　redox　active　sites　provided　by　the　HTC　coating　layer.　The　presence　of　the　amorphous　carbon　layers　on　the　felts　is　found　to　be　able　to　promote　the　mass/charge　transfer,　and　create　oxygenated/nitrogenated　active　sites　and　hence　enhances　wettability.　Consequently,　the　most　optimized　electrode　based　on　a　rational　approach　delivers　an　impressive　electrochemical　performance　toward　VRFBs　in　wide　range　of　current　densities　from　200　to　500　mA　cm−2.　The　voltage　efficiency　(VE)　of　GFs-HTC　is　much　higher　than　the　VEs　of　the　pristine　GFs,　especially　at　high　current　densities.　It　exhibits　a　4.18　times　increase　in　discharge　capacity　over　the　pristine　graphite　felt　respectively,　at　a　high　current　density　of　400　mA　cm−2.　The　enhanced　performance　is　attributed　to　the　abundant　active　sites　from　amorphous　hydrothermal　carbon,　which　facilitates　the　fast　electrochemical　kinetics　of　vanadium　redox　reactions.　This　work　evidences　that　the　glucose-derived　hydrothermal　carbons　as　energy　storage　booster　hold　great　promise　in　practical　VRFBs　application.　©　2019　Science　Press　and　Dalian　Institute　of　Chemical　Physics,　Chinese　Academy　of　Sciences