Li-rich　Li-Si　alloy-type　anodes　with　high　tap　density,　specific　capacity　and　cycling　stability　are　highly　demanded　for　pairing　Li-free　cathodes　to　develop　high　energy　Li　ion　batteries　(LIBs).　Here　we　fabricated　for　the　first　time　a　type　of　micron-scale　composite　of　Li21Si5　and　carbon　with　outstanding　electrochemical　performance,　which　has　unique　amorphous　core-nanocomposite　shell　structure　(denoted　as　a-Li21Si5@C).　The　thin　graphene　stacks　in　the　nanocomposite　shell　have　multiple　functions　of　constraining　effectively　the　volume　change　during　cycling,　providing　numerous　pathways　for　rapid　charge　transport　and　inhibiting　side　reactions　at　particle　surface.　Benefit　from　the　special　configuration,　the　a-Li21Si5@C　composite　has　a　reversible　specific　capacity　of　870　mAh　g(-1)　(2479　mAh　g(-1)　evaluated　from　Si　composition).　Moreover,　the　a-Li21Si5@C　composite　retains　a　specific　capacity　of　582　mAh　g(-1)　after　100　cycles,　which　exhibits　a　remarkably　increased　stability　as　compared　with　the　previous　micron-scale　Li-Si　alloys.　The　energy　density　of　the　full　cell　constructed　by　the　present　composite　and　sulfur　is　evaluated　as　2.6　times　high　as　that　of　the　commercial　LIBs.　The　studies　pave　the　way　for　developing　micron-scale　Li-rich　composites　as　high-performance　anode　candidates　for　advanced　LIBs.　(C)　2018　Elsevier　Ltd.　All　rights　reserved.