Recently,　Co-based　materials　have　been　widely　used　as　a　type　of　supercapacitor.　However,　Co-based　materials　are　highly　restricted　due　to　their　low　conductivity,　poor　cyclic　performance,　and　large　structural　changes　during　the　charge/discharge　process.　Carbon　materials　have　been　found　to　improve　the　electrochemistry　performance　of　Co(OH)2.　In　this　work,　sulfur　doping　was　used　to　enhance　the　electrochemistry　performance　of　Co(OH)2@nitrogen-doped　carbon　dots　(Co(OH)2@NC)　via　hydrothermal　approach.　Here,　as-prepared　S-Co(OH)2@NC　shows　an　excellent　specific　capacitance　of　730　F　g−1　at　1　A　g−1　(much　higher　than　that　of　pristine　Co(OH)2@NC　(592　F　g−1　at　1　A　g−1)).　An　asymmetric　supercapacitor　(ASC)　is　assembled　by　S-Co(OH)2@NC　(as　a　positive　electrode)　and　graphene　aerogels@NC　(as　a　negative　electrode),　which　presents　a　specific　energy　density　as　high　as　39.59　Wh　kg−1　with　a　power　density　of　639　W　kg−1.　Moreover,　the　ACS　manifests　extraordinary　cycle　stability　(75%　capacitance　retention　after　8500　cycles).　In　summary,　sulfur　doping　in　electrode　material　has　been　proven　as　an　efficient　approach　for　improving　the　electrochemical　performance　in　supercapacitor　devices.　©　2023,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.