Lithium batteries are also difficult to recycle. All the Lithium...

Lithium batteries are also difficult to recycle.
All the Lithium Grid connected batteries seem to have a 10 year usable life, because at that point if they haven't failed, they will only have 80% of the storage capacity that the batteries had when new. Flow batteries on the other hand have very little lost storage capacity.
So every Lithium battery in use now, will be replaced many times during the life of a building.
In 2018, CSIRO predicted that by 2036 Australia will exceed 100k tonnes of Lithium ion waste per year.
CSIRO: Australia is missing out on AU$3.1b industry in lithium-ion battery recycling | ZDNet
In 2018, the first Lithium Battery recycling centre opened in Victoria to great fanfair. It only has a capacity of ~200 tonnes per year. Far short of 100,000 tonnes that will be needed. We will need another 500 such recycling centres.

I'm going to assume that Vanadium Flow Batteries sold by AVL VSUN are similar to Redflow ZBM batteries in that recycling is easily done with current facilities and that the liquid (the bulk of the mass) can be put through a filtering process and reused again in other batteries.