On the one hand, two spin - 1 Ps atoms can collide to form two spin - 0 atoms; this process limits the density of the energy storage medium. (sciencedaily.com)
During this latter time, the spin - 1 states serve as an energy storage medium for the gamma ray laser: if they are switched into spin - 0 states, which constitutes the active gain medium that generates the fast pulse of 511 keV gamma rays. (sciencedaily.com)
In a battery, electrolytes are used as an energy storage medium. (discovermagazine.com)