> Lastly, in one of the ultimate tests of energy storage, the UCSB pyrimidone system achieves an energy density of about 1.6 MJ per kilogram, approximately double that of a standard lithium-ion battery at around 0.9 MJ/kg!

ScholarlyArticle: "Molecular solar thermal energy storage in Dewar pyrimidone beyond 1.6 MJ/kg" (2026) https://www.science.org/doi/10.1126/science.aec6413