From the article: "compared to a similar capacity battery, it's not only half the cost, the facility has a service life of 50 years, five to 10 times longer th

From the article: "compared to a similar capacity battery, it's not only half the cost, the facility has a service life of 50 years, five to 10 times longer than a battery." It doesn't explicit say what kind of battery, but a service life of 10 years suggests Li-ion.