“There are also tried-and-true alternatives to lithium-ion batteries that may be best suited to certain applications. For example, the vanadium flow battery has been around for decades, but it has a much lower energy density than lithium-ion—not great for electric cars. However, its long lifetime, reliability, safety, and rapid response rate may make it a better option for storing large amounts of energy from the electricity grid.”
Image source (http://www.nature.com/news/the-rechargeable-revolution-a-better-battery-1.14815)
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