They still make nickel iron batteries in China. They cost a little more than lead acid batteries but last much longer.
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On the other hand the only way known to me how to build a cheap and big storage yourself is to build a water container on the top of a hill or on the top of a tower. And to take the power out by a water turbine. To make a water container capable of 1 kWh is no that big a thing, if you happen to have a hill.
But you'll need something to pump the water up (a simple pump using solar heat? a wind machine? a combustion engine with a gasifier?..) and you'll need a water turbine and a generator. The efficency to get the power out of the water (once it is up there) is quite high, even 90%. But to get the water up there, that efficiency wouldn't be that high, maybe...
-hv