Ionic liquid-assisted exfoliation synthesis and in situ functionalization of silicon nanosheets.

Organic-functionalized silicon nanosheets are synthesized via a one-step ionic-liquid-assisted exfoliation of CaSi2 and in situ benzyl grafting. The grafted layer converts to a uniform carbon coating upon carbonization, providing conductivity and mechanical buffering against volume expansion and delivering 96.7% capacity retention after 1200 cycles at 0.5 A g-1 as a lithium-ion battery anode.