Energy conversion and storage devices, such as fuel cells, batteries, and redox-flow batteries, have made remarkable advances over the
last decade, and these are expected to play an ever growing role in meeting our energy needs. Critical challenges and opportunities for
these electrochemical energy and conversion devices are reviewed. As society moves toward greater reliance on renewable energy, such
as solar and wind, the need for energy storage increases. Cost and durability are barriers that must be addressed before these
electrochemical devices can play a significant role in addressing the world's energy challenge.