@mltivrs
Not sure what they're achieving by liquefying and freezing it, but simply compressing the air and putting it in tanks is supposed to be much more sustainable. Metal tanks require far simpler materials, no toxic degradation toward end-of-life (when is the end of life of a steel tank anyway?), are simpler to maintain and last incomparably longer than batteries, with no loss of capacity. Plus they're bootstrappable in far worse conditions than those required for battery manufacture, say in a world of widespread climate disasters and/or wars disrupting important supply chains. See also:
https://solar.lowtechmagazine.com/2018/05/ditch-the-batteries-off-grid-compressed-air-energy-storage/