There has been a lot of research in to replacing the anode in lithium ion batteries with materials other than graphite. Some have been successful, but only to limited levels.
A pure silicon anode would be a huge step up in energy storage, but there are a ton of issues that need solving down this path.
Tesla has slowly been working towards integrating more and more silicon in to their anodes. They announced plans to try and do effectively what SilaNano is doing here at their "battery day" last year, so it is a pretty big deal that they are pulling it off in a production battery.
Its not pure silicon. Its a silicon composite particle. The difference between other commercial silicons (like that in every Tesla) is that you not combining silicon (silicon oxide usually) with graphite.
The problem is we don't actually know what is in Sila Nanoparticles, but I am pretty sure its not 100% silicon.
Correct. Tesla, and many others, are working on similar concepts where it is silicon nano particles encapsulated with some other material. I'm betting that's what SilaNano is doing.
This, in theory, allows the silicon to expand without cracking, which has been the major issue with silicon anodes so far.
No, Tesla is actually not using Composite Nano particles.
They are using micro particles that are coated with a polymer and then mixed with graphite and a binder.
This is quite different. In that version you contain the silicon expansion not by having complex composite particle but rather by having the polymer contain the cracking.
Sila on the other hand is creating a more complex silicon particle that is partly empty and can expand without cracking. They have not released a picture, but Talga resources has a silicon composite product and they have a picture:
A pure silicon anode would be a huge step up in energy storage, but there are a ton of issues that need solving down this path.
Tesla has slowly been working towards integrating more and more silicon in to their anodes. They announced plans to try and do effectively what SilaNano is doing here at their "battery day" last year, so it is a pretty big deal that they are pulling it off in a production battery.