Lithium-ion is what the capitalists want you to use.
Nickel-hydrogen is three times heavier per unit of energy stored. Oh no. Sounds terrible. But it's –
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Cheap. $83 per kilowatt-hour (https://www.pnas.org/doi/10.1073/pnas.1809344115)
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Lasts 20,000 cycles compared to 400-1200 for lithium-ion, so far fewer will have to be produced and disposed of.
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Materials. This is the big one. Lithium is rare. It costs a lot of energy to mine, and mining produces a lot of wastewater and CIA coups. Nickel is abundant and cheaper, and causes less damage.
Nickely-hydrogen batteries are for applications where you want something good enough and care about the planet. Lithium-ion is when you need luxury and don't care about externalities.