Carbon　nanosheets　(CNSs)　having　both　graphite　microcrystalline　layers　and　amorphous　carbon　structures　are　prepared　by　a　space-confined　carbonization　strategy　using　glucose,　sucrose　and　starch　as　carbon　sources　which　are　inserted　into　the　confined　space　of　vermiculite　templates　by　liquid-phase　impregnation　intercalation.　The　microstructures　of　CNSs　are　strongly　depended　on　the　molecular　weight　of　carbon　precursors.　In　the　Starch-CNSs　synthesized　from　starch　with　larger　molecular　weight,　single　nanosheets　contain　more　ordered　graphite　microcrystalline　layers　and　fewer　microporous　defects　as　well　as　richer　oxygen-containing　functional　groups,　and　the　disordered　stacking　of　single　nanosheets　form　more　mesoporous　structures.　The　specific　surface　area　and　nanosheets　thickness　of　Starch-CNSs　are　400　m2·g−1　and　3.934　nm.　Starch-CNSs　as　anode　for　lithium-ion　batteries　exhibit　excellent　lithium　storage　properties,　combining　initial　Coulombic　efficiency　(56　%),　high　specific　capacity　(637mAh/g　at　0.05　A/g),　excellent　rate　performance　(253　mAh/g　at　2　A/g)　and　cycling　stability　(262　mAh/g　at　2　A/g　after　500　cycles).　These　results　show　the　CNSs　derived　from　larger　molecular　weights　outperform　these　from　lower　counterparts,　providing　strong　evidence　and　reference　for　selecting　suitable　molecular　weight　carbon　precursors　to　prepare　high-performance　CNSs　anode　for　lithium　ion　batteries.　©　2022　Elsevier　B.V.