Besides nuclear power, alternative renewable energies, e.g. wind, solar, and tidal energies, are also playing important roles in decarbonization. However, these non-nuclear alternative renewable energies are causing increasing load variability to the power grids due to their intermittent nature , so it is of vital importance to implement energy storage technology to mitigate such fluctuations. For long-term energy storage, converting and storing intermitting renewable electricity in the form of energy dense chemicals (e.g. H2 gas, H2O2) is of particular interest to the energy sector . On average, the net electrical energy density of U is estimated to be 43.3 MWh/kgU (Supplementary Note 13). In comparison, the gross energy densities of concentrated H2O2 (70% concentrated) and H2 gas, the state-of-art energy storage chemicals, were 0.58 kWh/kg and 33.35 kWh/kg, respectively . Hence, the net electrical power density of U is at least three and five orders of magnitude higher than the gross energy of H2 gas and concentrated H2O2, respectively. Therefore, U is an ideal candidate for power-to-chemical energy storage. For the PEC U extraction method, the compulsory energy input is calculated to be 70 ~ 125 kWh/kgU, without further optimization (Supplementary Note 11), which is only 0.16% ~ 0.29% of the energy density of the extracted U. This analysis implies that the PEC U extraction method has also great potential for energy storage applications.