Can Silicon be used as anode for Li-Ion batteries
Generally, heavier atoms means lower specific stored charge per mass.

Specific energy per mass depends of the cell redox systems, but also on the above.

Silicium, in contrary to carbon, does not form hexagonal planar structure with delocalized electrons like graphite, but prefers the diamond-like structure. 

The Li-ion cell anode is formed by lithium-graphite intercalate, for which does not exist Silicium analogue. If it had existed and the cell had been possible to create, the major difference would have been being heavier for the same mAh capacity.

Silicon anodes (thanks @andselisk  for the link) are possible, but not as analogue of the graphene structure  of graphite. The huge problem with them is material swelling in the charge state, limiting the anode life to few cycles. Few percents of silicium together with carbon can be used to increase somewhat the graphite anode capacity.