Are you kidding me? The 'first' was the Voltaic pile, copper and zinc. The first practical rechargeable was lead-acid. Li-ion is a relative newcomer, but had a sufficient power density to lead to a lot of applications which in turn led to a lot of research on improving Li-ion in a virtuous circle. We are pushing the limits of Li-ion and know that is sucks for some environments or application requirements, which is why people research alternatives.
This particular alternative is useful in some very specific niches in which Li-ion will _never_ be competitive.
