What are the latest challenges in lithium battery research, and do researchers feel that we have reached a mature stage in its development or is there still plenty of room to improve their energy density and lifespan?
There are some excellent reviews available in the literature about the issues addressed in your question. As an example, please find attached a link to an article by J.-M. Tarascon, published in the "Philosophical Transactions of the Royal Society". This piece really provides very interesting insight into the matter.
Vivek, attached another Trial; hope this will work; sorry that the breakthrough in this area in my opinion after over 40 years experience in electrochemistry will not be assessable.