We are only using lithium ion Batteries that come with a 10 year warranty. The Tesla Powerwall 2 Battery stores 14kW and is big enough for most homes. They have a price tag of $16,500 installed and including GST (as of 11/08/19)
We also have smaller batteries (4.8kW) that start at around $10,000 installed.
All of our batteries come with emergency power supply (EPS) which means that you have power in a power cut.