I just watched a segment on ABC where a researcher from the University of Wollongong talking about Sodium-Ion batteries. I had eve heard of them before.
The university is running a research program in association with Chinese interests and are about to undertake some large scale trial in NSW.
The researcher mentioned this type of battery won't replace tiny batteries in phones and tablets, but is absolutely targeted in larger batteries that might help renewables.
Sodium to potentially take market share from lithium/cobalt/nickel.
They will still need copper.
https://media.uow.edu.au/releases/UOW206870.html
https://media.uow.edu.au/releases/UOW212989.html
http://www.smh.com.au/business/energy/salt-could-supercharge-storage-batteries-20171013-gz0hr6.html
