Tungsten (W) is an exceptionally strong refractory metal,which is an important chemical element used in lamp filaments and in steel to increase hardness and strength.Recently,tungsten and related metals,including molybdenum,cobalt,vanadium,tantalum,niobium,rhenium,zirconium,hafnium as well as their alloys and compounds,are also found to be effective in preparing novel energy storage materials.The present issue consists of nine contributions with six review papers and three original research articles,