Same as above but I doubt the source of this information...

Same as above but I doubt the source of this information specifically because of point 2.
Silicon Nanowire expands/contracts too much charging/discharging leading to mechanical shear leading to low cycle life. It also is extremely expensive currently and so is not commercially viable. Elon has said on twitter recently that this kind of tech in a practical usable form is still 3-4 years off. Furthermore, when Elon was questioned on twitter about a link between Tesla and Amprius (the company that make silicon nano wires) he said:

"But actually nothing. Was surprised to hear they’re across the road. Adding silicon to carbon anode makes sense. We already do. Question is just what ratio of silicon to carbon & what shape? Silicon expands like crazy during discharge & comes apart, so cycle life is usually bad."