This research was focused on the lithium battery anode. Ideally we could just put a chunk of lithium in there but the stripping and deposition chemistry doesn't work well long term. Modern batteries use graphite instead. But of course you waste a significant amount of cell volume and weight with all of that carbon, and the potential is lower than Li metal. Alloying Li with silicon gets you properties more similar to Li.

So this paper talks about their efforts to make LiSi more viable as an anode. They gave it a coating to protect it from electrolyte side reactions and created a new gel electrolyte formation reaction. The capacity they report isn't remarkably higher than what's out there now since the cathode is the heaviest part of the cell.

As to the results I do have to say 60% capacity retention after 200 cycles is not nearly good enough for real world use. And I have no clue where they got the "1000 mile range" headline from.