5^th International Symposium on Materials for Energy Storage and Conversion (mESC-IS 2021) will take place for the fifth time in 14-17 September 2021. As before the symposium will provide a single roof, for a forum for discussion in recent progress made in four major activity areas, namely i) batteries and supercapacitors, ii) fuel/electrolytic cells iii) hydrides for energy storage and conversion and iv) active material development and recycling. The symposium will have a fair balance of plenary sessions on cross-cutting issues and the state of the art reviews plus in-depth parallel sessions on specific topics with invited, contributed papers and poster presentations.