In future years, I believe that scientists will discover a new chemical reaction that is stronger than that of the Li-ion. These new chemicals will be cheap, clean, and efficient. So then, we will be able to get millions of recharges rather than thousands, then safely dispose or recycle them. Also, the cases will be uncorrosive and non-toxic. To put it simply, future batteries will last nearly a lifetime and then can be recycled back into another working battery.