From memory after one viewing:
- smallest in class
- inert and incombustible
- indefinite shelf life
- 0-100% charge/discharge
- 100% efficiency (0 hysterisis)
- 10kWh in 4x3x2ft package, 600kWh in a shipping container
- positive ROI at top of price curve
I'm probably forgetting something.
It works by electroplating Zinc onto/off of a plastic membrane.