LLNL Scientists Uncover Recipe for Recoverable Carbon Dioxide Polymer as High-Energy Material

Lawrence Livermore National Laboratory (LLNL) researchers identified a first-of-its-kind carbon dioxide-equivalent polymer recoverable from high-pressure conditions on January 27, 2026. Led by scientist Stanimir Bonev, the team published their findings in Communications Chemistry, revealing a recipe for new energetic materials useful in propellants and explosives.

The innovation centers on transforming fleeting high-pressure atomic arrangements into stable materials under ambient conditions. Traditional carbon dioxide under compression forms dense structures, but they revert upon pressure release. LLNL's approach locks atoms into a covalently bonded network, creating a polymeric form that stores significantly more energy per unit mass or volume than ordinary CO2.

Researchers combined quantum molecular dynamics simulations with large-scale machine-learning models to predict polymer formation pathways. They explored broad pressure and temperature ranges, identifying optimal conditions. The pivotal strategy: compressing a mixture of carbon monoxide (CO) and oxygen (O2) instead of pure CO2. This lowers required pressures, enables flexible reactions, and favors amorphous solids over crystals for better stability post-decompression.

• Quantum simulations modeled high-pressure behavior and release dynamics.
• Machine learning accelerated exploration of conditions.
• CO + O2 mixture forms carbon-carbon bonds, stabilizing the structure.

Carbon-carbon bonds emerge readily in the mixture, forming a distinct structure that persists after pressure release. Amorphous nature avoids crystal defects that destabilize upon decompression. Bonev explained: "A polymeric form of carbon dioxide stores far more energy... representing a high-energy-density material." This distinguishes it from transient high-pressure phases.

Energetic materials from this polymer could advance propellants and explosives with superior energy density. The method extends to light-element systems like carbon, oxygen, nitrogen, hydrogen, potentially yielding new functional materials. LLNL provides a concrete experimental target: compress CO-O2 mixtures under specified conditions to synthesize and recover the polymer.

Unlike pure CO2 studies, which fail at ambient recovery, the mixture approach succeeds at lower pressures. Previous efforts yielded only transient phases; this identifies a stable, amorphous polymer. No direct competitors match this CO2-equivalent recoverability, positioning LLNL's work as pioneering in energetic material design.

Experimental validation could follow simulations, with machine-learning guidance optimizing synthesis. Related LLNL code developments for non-equilibrium simulations, like foam targets at National Ignition Facility, suggest synergies for atomistic-hydrodynamic modeling. Success here may enable materials releasing energy controllably, advancing defense and aerospace applications backed by the polymer's predicted high density.