Storage type  Specific energy  (MJ /kg) Energy density (MJ/L ) Peak recovery efficiency    % Practical recovery efficiency  % Arbitrary Antimatter   89,875,517,874 depends on density  Deuterium–tritium fusion   576,000,000 [ 1]      Uranium-235  fissile isotope 144,000,000 [ 1]     1,500,000,000  Natural uranium  (99.3% U-238, 0.7% U-235) in fast breeder reactor   86,000,000  Reactor-grade uranium  (3.5% U-235) in light-water reactor   3,456,000  35%    Pu-238  α-decay 2,200,000  Hf-178m2  isomer   1,326,000 17,649,060  Natural uranium  (0.7% U235) in light-water reactor   443,000  35%    Ta-180m isomer   41,340 689,964  Metallic hydrogen  (recombination energy) 216 [ 2]      Specific orbital energy  of Low Earth orbit  (approximate) 33.0  Beryllium  + Oxygen   23.9 [ 3]      Lithium  + Fluorine   23.75[  citation needed    ]   Octaazacubane  potential explosive 22.9 [ 4]      Hydrogen  + Oxygen   13.4 [ 5]      Gasoline  + Oxygen  –> Derived from Gasoline   13.3[  citation needed    ]   Dinitroacetylene  explosive - computed[  citation needed    ]  9.8  Octanitrocubane  explosive 8.5 [ 6]     16.9 [ 7]      Tetranitrotetrahedrane  explosive - computed[  citation needed    ]  8.3  Heptanitrocubane  explosive - computed[  citation needed    ]  8.2  Sodium  (reacted with chlorine)[  citation needed    ]  7.0349  Hexanitrobenzene  explosive 7 [ 8]      Tetranitrocubane  explosive - computed[  citation needed    ]  6.95  Ammonal  (Al+NH4 NO3   oxidizer )[  citation needed    ]  6.9 12.7  Tetranitromethane  + hydrazine  bipropellant - computed[  citation needed    ]  6.6  Nitroglycerin   6.38 [ 9]     10.2 [ 10]      ANFO -ANNM  [  citation needed    ]  6.26  battery, Lithium–air   6.12  Octogen  (HMX) 5.7 [ 9]     10.8 [ 11]      TNT   [ 12]     4.610 6.92 Copper Thermite   (Al + CuO  as oxidizer )[  citation needed    ]  4.13 20.9  Thermite  (powder Al + Fe2 O3   as oxidizer ) 4.00 18.4  Hydrogen peroxide  decomposition (as monopropellant ) 2.7 3.8  battery, Lithium-ion nanowire   2.54 29 95%[  clarification needed    ]  [ 13]      battery, Lithium Thionyl Chloride (LiSOCl2)   [ 14]     2.5  Water  220.64 bar, 373.8  °C[  citation needed    ] [  clarification needed    ]  1.968 0.708  Kinetic energy penetrator  [  clarification needed    ]  1.9 30  battery, Lithium–Sulfur   [ 15]     1.80 [ 16]     1.26  battery, Fluoride-ion  [  citation needed    ]  1.7 2.8  battery, Hydrogen closed cycle H fuel cell   [ 17]     1.62  Hydrazine  decomposition (as monopropellant ) 1.6 1.6  Ammonium nitrate  decomposition (as monopropellant ) 1.4 2.5  Thermal Energy Capacity of Molten Salt   1[  citation needed    ]  98% [ 18]      Molecular spring  approximate[  citation needed    ]  1  battery, Lithium–Manganese   [ 19]     [ 20]     0.83-1.01 1.98-2.09  battery, Sodium–Sulfur   0.72 [ 21]     1.23[  citation needed    ]  85% [ 22]      battery, Lithium-ion   [ 23]     [ 24]     0.46-0.72 0.83-3.6 [ 25]     95% [ 26]      battery, Sodium–Nickel Chloride , High Temperature 0.56  battery, Zinc–manganese (alkaline) , long life design [ 19]     [ 23]     0.4-0.59 1.15-1.43  battery, Silver-oxide   [ 19]     0.47 1.8  Flywheel   0.36-0.5 [ 27]     [ 28]      5.56 × 45 mm NATO  bullet muzzle energy density[  clarification needed    ]  0.4 3.2  battery, Nickel–metal hydride (NiMH) , low power design as used in consumer batteries [ 29]     0.4 1.55  Liquid Nitrogen   0.349  Water  – Enthalpy of Fusion   0.334 0.334  battery, Zinc–Bromine flow (ZnBr)   [ 30]     0.27  battery, Nickel–metal hydride (NiMH) , High-Power design as used in cars [ 31]     0.250 0.493  battery, Nickel–Cadmium (NiCd)   [ 23]     0.14 1.08 80% [ 26]      battery, Zinc–Carbon   [ 23]     0.13 0.331  battery, Lead–acid   [ 23]     0.14 0.36  battery, Vanadium redox   0.09[  citation needed    ]  0.1188 70 70-75% battery, Vanadium–Bromide redox   0.18 0.252 80%–90% [ 32]      Capacitor  Ultracapacitor   0.0199 [ 33]     0.050[  citation needed    ]   Capacitor  Supercapacitor   0.01[  citation needed    ]  80%–98.5% [ 34]     39%–70% [ 34]      Superconducting magnetic energy storage   0 0.008 [ 35]     >95%  Capacitor   0.002 [ 36]      Neodymium magnet   0.003 [ 37]      Ferrite magnet   0.0003 [ 37]      Spring power  (clock spring), torsion spring   0.0003 [ 38]     0.0006 Storage type Energy density by mass (MJ/kg) Energy density by volume (MJ/L ) Peak recovery efficiency  % Practical recovery efficiency  %