A new salt based battery from US based Aquion will allow mass storage of solar generated power more cheaply than lithium iron or lead acid batteries.
The approach uses a bath of salts to store the charge without the chemical deterioration and inefficiencies found in most existing batteries. Batteries using highly reactive chemicals gradually wear out as the chemicals become polluted with constant re-use.
Similar technology was developed at the University of New South Wales thirty years ago using Vanadium salts, but was not successfully commercialized.
Solar and salt water battery storage used to create “nanogrid” of future
The unique solar and storage system designed for IIT will use alternating and direct current loads while charging batteries at the same time, allowing the nanogrid to run independent of the rest of the campus, as an islanded off-grid system.
https://onestepoffthegrid.com.au/solar-salt-water-battery-storage-used-create-nanogrid-future/
http://www.solarchoice.net.au/blog/aquion-saltwater-batteries-q-and-a
http://www.ceic.unsw.edu.au/centers/vrb/about-us/history-of-vanadium-redox-battery.html
http://www.vfuel.com.au/company.htm