I think I found the actual paper: http://zeppola.mit.edu/pubs/FvRu_Thermal_Reversal_AngewChem.... [ http://zeppola.mit.edu/index.php?option=com_joodb&view=a... ].

    * It stores energy from light, at 350nm (near UV)
    * It releases energy when catalyzed or heated (barrier is 30 kcal/mol)
    * It stores 0.2 MJ/Kg (vs. 0.5 MJ/Kg for lithium ion batteries)
    * Using iron instead of ruthenium lowers the energy barrier for returning to the ground state, enough that it's useless at normal temperatures