In　the　present　work　a　composite　counter　electrode　of　graphene　nanosheets　grafted　cobalt　sulfide　was　fabricated　through　a　facile　synthetic　route,　in　which　cobalt　sulfide　nanoparticles　were　successfully　grafted　on　the　surface　of　graphene　nanosheets.　Used　as　a　counter　electrode　in　DSSC,　a　power　conversion　efficiency　of　7.28%　can　be　achieved.　Such　a　result　might　be　contributed　to　the　facts　that　this　counter　electrode　composed　of　graphene　nanosheets　grafted　cobalt　sulfide　has　a　good　stability　and　electrochemical　catalytic　performance　toward　triiodide　reduction　reaction.　©　2019　Elsevier　B.V.